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0N/A# This file is in the public domain, so clarified as of
0N/A# 2009-05-17 by Arthur David Olson.
# also includes Central America and the Caribbean
# This data is by no means authoritative; if you think you know better,
# go ahead and edit the file (and please send any changes to
# tz@elsie.nci.nih.gov for general use in the future).
# From Paul Eggert (1999-03-22):
# A reliable and entertaining source about time zones is
# Derek Howse, Greenwich time and longitude, Philip Wilson Publishers (1997).
###############################################################################
# From Paul Eggert (1999-03-31):
# Howse writes (pp 121-125) that time zones were invented by
# Professor Charles Ferdinand Dowd (1825-1904),
# Principal of Temple Grove Ladies' Seminary (Saratoga Springs, NY).
# His pamphlet ``A System of National Time for Railroads'' (1870)
# was the result of his proposals at the Convention of Railroad Trunk Lines
# in New York City (1869-10). His 1870 proposal was based on Washington, DC,
# but in 1872-05 he moved the proposed origin to Greenwich.
# His proposal was adopted by the railroads on 1883-11-18 at 12:00,
# and the most of the country soon followed suit.
# From Paul Eggert (2005-04-16):
# That 1883 transition occurred at 12:00 new time, not at 12:00 old time.
# See p 46 of David Prerau, Seize the daylight, Thunder's Mouth Press (2005).
# From Paul Eggert (2006-03-22):
# A good source for time zone historical data in the US is
# Thomas G. Shanks, The American Atlas (5th edition),
# San Diego: ACS Publications, Inc. (1991).
# Make sure you have the errata sheet; the book is somewhat useless without it.
# It is the source for most of the pre-1991 US entries below.
# From Paul Eggert (2001-03-06):
# Daylight Saving Time was first suggested as a joke by Benjamin Franklin
# in his whimsical essay ``An Economical Project for Diminishing the Cost
# of Light'' published in the Journal de Paris (1784-04-26).
# Not everyone is happy with the results:
# I don't really care how time is reckoned so long as there is some
# agreement about it, but I object to being told that I am saving
# daylight when my reason tells me that I am doing nothing of the kind.
# I even object to the implication that I am wasting something
# valuable if I stay in bed after the sun has risen. As an admirer
# of moonlight I resent the bossy insistence of those who want to
# reduce my time for enjoying it. At the back of the Daylight Saving
# scheme I detect the bony, blue-fingered hand of Puritanism, eager
# to push people into bed earlier, and get them up earlier, to make
# them healthy, wealthy and wise in spite of themselves.
# -- Robertson Davies, The diary of Samuel Marchbanks,
# Clarke, Irwin (1947), XIX, Sunday
# For more about the first ten years of DST in the United States, see
# Ten years of daylight saving from the Pittsburgh standpoint
# (Carnegie Library of Pittsburgh, 1927)</a>.
# Shanks says that DST was called "War Time" in the US in 1918 and 1919.
# However, DST was imposed by the Standard Time Act of 1918, which
# was the first nationwide legal time standard, and apparently
# time was just called "Standard Time" or "Daylight Saving Time".
# From Arthur David Olson:
# US Daylight Saving Time ended on the last Sunday of *October* in 1974.
# See, for example, the front page of the Saturday, 1974-10-26
# and Sunday, 1974-10-27 editions of the Washington Post.
# From Arthur David Olson:
# Before the Uniform Time Act of 1966 took effect in 1967, observance of
# Daylight Saving Time in the US was by local option, except during wartime.
# From Arthur David Olson (2000-09-25):
# Last night I heard part of a rebroadcast of a 1945 Arch Oboler radio drama.
# In the introduction, Oboler spoke of "Eastern Peace Time."
# An AltaVista search turned up
# "When the time is announced over the radio now, it is 'Eastern Peace
# Time' instead of the old familiar 'Eastern War Time.' Peace is wonderful."
# </a> (August 1945) by way of confirmation.
# From Joseph Gallant citing
# George H. Douglas, _The Early Days of Radio Broadcasting_ (1987):
# At 7
P.M. (Eastern War Time) [on 1945-08-14], the networks were set
# to switch to London for Attlee's address, but the American people
# never got to hear his speech live. According to one press account,
# CBS' Bob Trout was first to announce the word of Japan's surrender,
# but a few seconds later, NBC, ABC and Mutual also flashed the word
# of surrender, all of whom interrupting the bells of Big Ben in
# London which were to precede Mr. Attlee's speech.
# From Paul Eggert (2003-02-09): It was Robert St John, not Bob Trout. From
# Myrna Oliver's obituary of St John on page B16 of today's Los Angeles Times:
# ... a war-weary
U.S. clung to radios, awaiting word of Japan's surrender.
# Any announcement from Asia would reach St. John's New York newsroom on a
# wire service teletype machine, which had prescribed signals for major news.
# Associated Press, for example, would ring five bells before spewing out
# typed copy of an important story, and 10 bells for news "of transcendental
# On Aug. 14, stalling while talking steadily into the NBC networks' open
# microphone, St. John heard five bells and waited only to hear a sixth bell,
# before announcing confidently: "Ladies and gentlemen, World War II is over.
# The Japanese have agreed to our surrender terms."
# He had scored a 20-second scoop on other broadcasters.
# From Arthur David Olson (2005-08-22):
# Paul has been careful to use the "US" rules only in those locations
# that are part of the United States; this reflects the real scope of
#
U.S. government action. So even though the "US" rules have changed
# in the latest release, other countries won't be affected.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule US 1918 1919 - Mar lastSun 2:00 1:00 D
Rule US 1918 1919 - Oct lastSun 2:00 0 S
Rule US 1942 only - Feb 9 2:00 1:00 W # War
Rule US 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule US 1945 only - Sep 30 2:00 0 S
Rule US 1967 2006 - Oct lastSun 2:00 0 S
Rule US 1967 1973 - Apr lastSun 2:00 1:00 D
Rule US 1974 only - Jan 6 2:00 1:00 D
Rule US 1975 only - Feb 23 2:00 1:00 D
Rule US 1976 1986 - Apr lastSun 2:00 1:00 D
Rule US 1987 2006 - Apr Sun>=1 2:00 1:00 D
Rule US 2007 max - Mar Sun>=8 2:00 1:00 D
Rule US 2007 max - Nov Sun>=1 2:00 0 S
# From Arthur David Olson, 2005-12-19
# We generate the files specified below to guard against old files with
# obsolete information being left in the time zone binary directory.
# We limit the list to names that have appeared in previous versions of
# this time zone package.
# We do these as separate Zones rather than as Links to avoid problems if
# a particular place changes whether it observes DST.
# We put these specifications here in the northamerica file both to
# increase the chances that they'll actually get compiled and to
# avoid the need to duplicate the US rules in another file.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone EST5EDT -5:00 US E%sT
Zone CST6CDT -6:00 US C%sT
Zone MST7MDT -7:00 US M%sT
Zone PST8PDT -8:00 US P%sT
# From Bob Devine (1988-01-28):
#
...Alaska (and Hawaii) had the timezone names changed in 1967.
# Pacific Standard Time(PST) -same-
# Yukon Standard Time(YST) -same-
# Central Alaska
S.T. (CAT) Alaska-Hawaii St[an]dard Time (AHST)
# Nome Standard Time (NT) Bering Standard Time (BST)
#
...Alaska's timezone lines were redrawn in 1983 to give only 2 tz.
# The YST zone now covers nearly all of the state, AHST just part
# of the Aleutian islands. No DST.
# From Paul Eggert (1995-12-19):
# The tables below use `NST', not `NT', for Nome Standard Time.
# I invented `CAWT' for Central Alaska War Time.
# From U. S. Naval Observatory (1989-01-19):
# USA EASTERN 5 H BEHIND UTC NEW YORK, WASHINGTON
# USA EASTERN 4 H BEHIND UTC APR 3 - OCT 30
# USA CENTRAL 6 H BEHIND UTC CHICAGO, HOUSTON
# USA CENTRAL 5 H BEHIND UTC APR 3 - OCT 30
# USA MOUNTAIN 7 H BEHIND UTC DENVER
# USA MOUNTAIN 6 H BEHIND UTC APR 3 - OCT 30
# USA PACIFIC 8 H BEHIND UTC
L.A., SAN FRANCISCO
# USA PACIFIC 7 H BEHIND UTC APR 3 - OCT 30
# USA ALASKA STD 9 H BEHIND UTC MOST OF ALASKA (AKST)
# USA ALASKA STD 8 H BEHIND UTC APR 3 - OCT 30 (AKDT)
# USA ALEUTIAN 10 H BEHIND UTC ISLANDS WEST OF 170W
# USA - " - 9 H BEHIND UTC APR 3 - OCT 30
# USA HAWAII 10 H BEHIND UTC
# USA BERING 11 H BEHIND UTC SAMOA, MIDWAY
# From Arthur David Olson (1989-01-21):
# The above dates are for 1988.
# Note the "AKST" and "AKDT" abbreviations, the claim that there's
# no DST in Samoa, and the claim that there is DST in Alaska and the
# From Arthur David Olson (1988-02-13):
# Legal standard time zone names, from United States Code (1982 Edition and
# Supplement III), Title 15, Chapter 6, Section 260 and forward. First, names
# up to 1967-04-01 (when most provisions of the Uniform Time Act of 1966
# took effect), as explained in sections 263 and 261:
# United States standard eastern time
# United States standard mountain time
# United States standard central time
# United States standard Pacific time
# United States standard Alaska time
# Next, names from 1967-04-01 until 1983-11-30 (the date for
# Alaska-Hawaii standard time
# Hawaii-Aleutian standard time
# The law doesn't give abbreviations.
# From Paul Eggert (2000-01-08), following a heads-up from Rives McDow:
# Public law 106-564 (2000-12-23) introduced the abbreviation
# "Chamorro Standard Time" for time in Guam and the Northern Marianas.
# See the file "australasia".
# From Arthur David Olson, 2005-08-09
# The following was signed into law on 2005-08-08.
#
H.R. 6, Energy Policy Act of 2005, SEC. 110. DAYLIGHT SAVINGS.
# (a) Amendment- Section 3(a) of the Uniform Time Act of 1966 (15
#
U.S.C. 260a(a)) is amended--
# (1) by striking `first Sunday of April' and inserting `second
# (2) by striking `last Sunday of October' and inserting `first
# (b) Effective Date- Subsection (a) shall take effect 1 year after the
# date of enactment of this Act or March 1, 2007, whichever is later.
# (c) Report to Congress- Not later than 9 months after the effective
# date stated in subsection (b), the Secretary shall report to Congress
# on the impact of this section on energy consumption in the United
# (d) Right to Revert- Congress retains the right to revert the
# Daylight Saving Time back to the 2005 time schedules once the
# Department study is complete.
# US eastern time, represented by New York
# Connecticut, Delaware, District of Columbia, most of Florida,
# Georgia, southeast Indiana (Dearborn and Ohio counties), eastern Kentucky
# New Hampshire, New Jersey, New York, North Carolina, Ohio,
# Pennsylvania, Rhode Island, South Carolina, eastern Tennessee,
# Vermont, Virginia, West Virginia
# From Dave Cantor (2004-11-02):
# Early this summer I had the occasion to visit the Mount Washington
# Observatory weather station atop (of course!) Mount Washington [, NH]....
# One of the staff members said that the station was on Eastern Standard Time
# and didn't change their clocks for Daylight Saving ... so that their
# reports will always have times which are 5 hours behind UTC.
# From Paul Eggert (2005-08-26):
# According to today's Huntsville Times
# a few towns on Alabama's "eastern border with Georgia, such as Phenix City
# in Russell County, Lanett in Chambers County and some towns in Lee County,
# set their watches and clocks on Eastern time." It quotes
H.H. "Bubba"
# Roberts, city administrator in Phenix City. as saying "We are in the Central
# time zone, but we do go by the Eastern time zone because so many people work
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule NYC 1920 only - Mar lastSun 2:00 1:00 D
Rule NYC 1920 only - Oct lastSun 2:00 0 S
Rule NYC 1921 1966 - Apr lastSun 2:00 1:00 D
Rule NYC 1921 1954 - Sep lastSun 2:00 0 S
Rule NYC 1955 1966 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# US central time, represented by Chicago
# Alabama, Arkansas, Florida panhandle (Bay, Calhoun, Escambia,
# Gulf, Holmes, Jackson, Okaloosa, Santa Rosa, Walton, and
# Washington counties), Illinois, western Indiana
# (Gibson, Jasper, Lake, LaPorte, Newton, Porter, Posey, Spencer,
# Vanderburgh, and Warrick counties), Iowa, most of Kansas, western
# Kentucky, Louisiana, Minnesota, Mississippi, Missouri, eastern
# Nebraska, eastern North Dakota, Oklahoma, eastern South Dakota,
# western Tennessee, most of Texas, Wisconsin
# From Larry M. Smith (2006-04-26) re Wisconsin:
# is currently enforced at the 01:00 time of change. Because the local
# "bar time" in the state corresponds to 02:00, a number of citations
# are issued for the "sale of class 'B' alcohol after prohibited
# hours" within the deviated hour of this change every year....
# From Douglas R. Bomberg (2007-03-12):
# Wisconsin has enacted (nearly eleventh-hour) legislation to get WI
# Statue 175 closer in synch with the US Congress' intent....
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Chicago 1920 only - Jun 13 2:00 1:00 D
Rule Chicago 1920 1921 - Oct lastSun 2:00 0 S
Rule Chicago 1921 only - Mar lastSun 2:00 1:00 D
Rule Chicago 1922 1966 - Apr lastSun 2:00 1:00 D
Rule Chicago 1922 1954 - Sep lastSun 2:00 0 S
Rule Chicago 1955 1966 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-6:00 Chicago C%sT 1936 Mar 1 2:00
-5:00 - EST 1936 Nov 15 2:00
# Oliver County, ND switched from mountain to central time on 1992-10-25.
-7:00 US M%sT 1992 Oct 25 02:00
# Morton County, ND, switched from mountain to central time on
# 2003-10-26, except for the area around Mandan which was already central time.
# Officially this switch also included part of Sioux County, and
# Jones, Mellette, and Todd Counties in South Dakota;
# but in practice these other counties were already observing central time.
-7:00 US M%sT 2003 Oct 26 02:00
# From Josh Findley (2011-01-21):
#
...it appears that Mercer County, North Dakota, changed from the
# mountain time zone to the central time zone at the last transition from
# daylight-saving to standard time (on Nov. 7, 2010):
# From Andy Lipscomb (2011-01-24):
#
...according to the Census Bureau, the largest city is Beulah (although
# it's commonly referred to as Beulah-Hazen, with Hazen being the next
# largest city in Mercer County). Google Maps places Beulah's city hall
# at 4715'51" north, 10146'40" west, which yields an offset of 6h47'07".
-7:00 US M%sT 2010 Nov 7 2:00
# US mountain time, represented by Denver
# Colorado, far western Kansas, Montana, western
# Nebraska, Nevada border (Jackpot, Owyhee, and Mountain City),
# New Mexico, southwestern North Dakota,
# western South Dakota, far western Texas (El Paso County, Hudspeth County,
# and Pine Springs and Nickel Creek in Culberson County), Utah, Wyoming
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Denver 1920 1921 - Mar lastSun 2:00 1:00 D
Rule Denver 1920 only - Oct lastSun 2:00 0 S
Rule Denver 1921 only - May 22 2:00 0 S
Rule Denver 1965 1966 - Apr lastSun 2:00 1:00 D
Rule Denver 1965 1966 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# US Pacific time, represented by Los Angeles
# California, northern Idaho (Benewah, Bonner, Boundary, Clearwater,
# Idaho, Kootenai, Latah, Lewis, Nez Perce, and Shoshone counties,
# and the northern three-quarters of Idaho county),
# most of Nevada, most of Oregon, and Washington
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule CA 1948 only - Mar 14 2:00 1:00 D
Rule CA 1949 only - Jan 1 2:00 0 S
Rule CA 1950 1966 - Apr lastSun 2:00 1:00 D
Rule CA 1950 1961 - Sep lastSun 2:00 0 S
Rule CA 1962 1966 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# AK%sT is the modern abbreviation for -9:00 per USNO.
# From Paul Eggert (2001-05-30):
# Howse writes that Alaska switched from the Julian to the Gregorian calendar,
# and from east-of-GMT to west-of-GMT days, when the US bought it from Russia.
# This was on 1867-10-18, a Friday; the previous day was 1867-10-06 Julian,
# also a Friday. Include only the time zone part of this transition,
# ignoring the switch from Julian to Gregorian, since we can't represent
# As far as we know, none of the exact locations mentioned below were
# permanently inhabited in 1867 by anyone using either calendar.
# (Yakutat was colonized by the Russians in 1799, but the settlement
# was destroyed in 1805 by a Yakutat-kon war party.) However, there
# were nearby inhabitants in some cases and for our purposes perhaps
# it's best to simply use the official transition.
# From Steve Ferguson (2011-01-31):
# The author lives in Alaska and many of the references listed are only
# available to Alaskan residents.
# From Arthur David Olson (2011-02-01):
# Here's database-relevant material from the 2001 "Alaska History" article:
# 1980, Juneau and other nearby communities would move to Yukon Time.
# Sitka, Petersburg, Wrangell, and Ketchikan, however, would remain on
#
...on September 22, 1980, DOT Secretary Neil E. Goldschmidt rescinded the
# Department's September 1979 decision. Juneau and other communities in
# northern Southeast reverted to Pacific Time on October 26.
# On October 28 [1983]
...the Metlakatla Indian Community Council voted
# unanimously to keep the reservation on Pacific Time.
# According to DOT official Joanne Petrie, Indian reservations are not
# bound to follow time zones imposed by neighboring jurisdictions.
# (The last is consistent with how the database now handles the Navajo
# From Arthur David Olson (2011-02-09):
# I just spoke by phone with a staff member at the Metlakatla Indian
# Community office (using contact information available at
# It's shortly after 1:00 here on the east coast of the United States;
# the staffer said it was shortly after 10:00 there. When I asked whether
# that meant they were on Pacific time, they said no--they were on their
# own time. I asked about daylight saving; they said it wasn't used. I
# did not inquire about practices in the past.
# From Arthur David Olson (2011-08-17):
# For lack of better information, assume that Metlakatla's
# abandonment of use of daylight saving resulted from the 1983 vote.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-8:57:41 - LMT 1900 Aug 20 12:00
-8:00 US P%sT 1980 Apr 27 2:00
-9:00 US Y%sT 1980 Oct 26 2:00
-8:00 US P%sT 1983 Oct 30 2:00
-9:00 US Y%sT 1983 Nov 30
-9:01:13 - LMT 1900 Aug 20 12:00
-8:00 US P%sT 1983 Oct 30 2:00
-9:00 US Y%sT 1983 Nov 30
-8:46:18 - LMT 1900 Aug 20 12:00
-8:00 US P%sT 1983 Oct 30 2:00
-9:18:55 - LMT 1900 Aug 20 12:00
-9:00 US Y%sT 1983 Nov 30
-9:59:36 - LMT 1900 Aug 20 12:00
-10:00 US AH%sT 1983 Oct 30 2:00
-9:00 US Y%sT 1983 Nov 30
-11:01:38 - LMT 1900 Aug 20 12:00
-11:00 US B%sT 1983 Oct 30 2:00
-9:00 US Y%sT 1983 Nov 30
-11:46:38 - LMT 1900 Aug 20 12:00
-11:00 US B%sT 1983 Oct 30 2:00
-10:00 US AH%sT 1983 Nov 30
# The following switches don't quite make our 1970 cutoff.
# Shanks writes that part of southwest Alaska (
e.g. Aniak)
# switched from -11:00 to -10:00 on 1968-09-22 at 02:00,
# and another part (
e.g. Akiak) made the same switch five weeks later.
# From David Flater (2004-11-09):
# Historic Preservation Commission, provided this information, which
# suggests that Unalaska deviated from statutory time from early 1967
# Minutes of the Unalaska City Council Meeting, January 10, 1967:
# "Except for St. Paul and Akutan, Unalaska is the only important
# location not on Alaska Standard Time. The following resolution was
# made by William Robinson and seconded by Henry Swanson: Be it
# resolved that the City of Unalaska hereby goes to Alaska Standard
# Time as of midnight Friday, January 13, 1967 (1
A.M. Saturday,
# January 14, Alaska Standard Time.) This resolution was passed with
# three votes for and one against."
# From Arthur David Olson (2010-12-09):
# "Hawaiian Time" by Robert C. Schmitt and Doak C. Cox appears on pages 207-225
# of volume 26 of The Hawaiian Journal of History (1992). As of 2010-12-09,
# the article is available at
# and indicates that standard time was adopted effective noon, January
# 13, 1896 (page 218), that in "1933, the Legislature decreed daylight
# saving for the period between the last Sunday of each April and the
# last Sunday of each September, but less than a month later repealed the
# act," (page 220), that year-round daylight saving time was in effect
# from 1942-02-09 to 1945-09-30 (page 221, with no time of day given for
# when clocks changed) and that clocks were changed by 30 minutes
# effective the second Sunday of June, 1947 (page 219, with no time of
# day given for when clocks changed). A footnote for the 1933 changes
# cites Session Laws of Hawaii 1933, "Act. 90 (approved 26 Apr. 1933)
# and Act 163 (approved 21 May 1933)."
# From Arthur David Olson (2011-01-19):
# The following is from "Laws of the Territory of Hawaii Passed by the
# Seventeenth Legislature: Regular Session 1933," available (as of
# 2011-01-19) at American University's Pence Law Library. Page 85: "Act
#
90...At 2 o'clock ante meridian of the last Sunday in April of each
# year, the standard time of this Territory shall be advanced one
#
hour...This Act shall take effect upon its approval. Approved this 26th
# day of April, A. D. 1933. LAWRENCE M JUDD, Governor of the Territory of
# Hawaii." Page 172: "Act
163...Act 90 of the Session Laws of 1933 is
# which date the standard time of this Territory shall be restored to
# that existing immediately prior to the taking effect of said Act 90.
# Approved this 21st day of May, A. D. 1933. LAWRENCE M. JUDD, Governor
# of the Territory of Hawaii."
# Note that 1933-05-21 was a Sunday.
# We're left to guess the time of day when Act 163 was approved; guess noon.
-10:30 - HST 1933 Apr 30 2:00 #Laws 1933
-10:30 1:00 HDT 1933 May 21 12:00 #Laws 1933+12
-10:30 - HST 1942 Feb 09 2:00 #Schmitt&Cox+2
-10:30 1:00 HDT 1945 Sep 30 2:00 #Schmitt&Cox+2
-10:30 - HST 1947 Jun 8 2:00 #Schmitt&Cox+2
# Now we turn to US areas that have diverged from the consensus since 1970.
# Arizona mostly uses MST.
# From Paul Eggert (2002-10-20):
# The information in the rest of this paragraph is derived from the
# Daylight Saving Time web page (2002-01-23)</a> maintained by the
# Arizona State Library, Archives and Public Records.
# Between 1944-01-01 and 1944-04-01 the State of Arizona used standard
# time, but by federal law railroads, airlines, bus lines, military
# personnel, and some engaged in interstate commerce continued to
# observe war (
i.e., daylight saving) time. The 1944-03-17 Phoenix
# Gazette says that was the date the law changed, and that 04-01 was
# the date the state's clocks would change. In 1945 the State of
# Arizona used standard time all year, again with exceptions only as
# mandated by federal law. Arizona observed DST in 1967, but Arizona
# Laws 1968, ch. 183 (effective 1968-03-21) repealed DST.
# Shanks says the 1944 experiment came to an end on 1944-03-17.
# Go with the Arizona State Library instead.
-7:00 US M%sT 1944 Jan 1 00:01
-7:00 - MST 1944 Apr 1 00:01
-7:00 US M%sT 1944 Oct 1 00:01
-7:00 US M%sT 1968 Mar 21
# From Arthur David Olson (1988-02-13):
# A writer from the Inter Tribal Council of Arizona, Inc.,
# notes in private correspondence dated 1987-12-28 that "Presently, only the
# Navajo Nation participates in the Daylight Saving Time policy, due to its
# large size and location in three states." (The "only" means that other
# tribal nations don't use DST.)
# Southern Idaho (Ada, Adams, Bannock, Bear Lake, Bingham, Blaine,
# Boise, Bonneville, Butte, Camas, Canyon, Caribou, Cassia, Clark,
# Custer, Elmore, Franklin, Fremont, Gem, Gooding, Jefferson, Jerome,
# Lemhi, Lincoln, Madison, Minidoka, Oneida, Owyhee, Payette, Power,
# Teton, Twin Falls, Valley, Washington counties, and the southern
# quarter of Idaho county) and eastern Oregon (most of Malheur County)
# switched four weeks late in 1974.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-8:00 US P%sT 1923 May 13 2:00
-7:00 - MST 1974 Feb 3 2:00
# For a map of Indiana's time zone regions, see:
# What time is it in Indiana?
# From Paul Eggert (2007-08-17):
# with the following exceptions:
# - Gibson, Jasper, Lake, LaPorte, Newton, Porter, Posey, Spencer,
# - Clark, Floyd, and Harrison counties have been like
# - Crawford, Daviess, Dubois, Knox, Martin, Perry, Pike, Pulaski, Starke,
# and Switzerland counties have their own time zone histories as noted below.
# Shanks partitioned Indiana into 345 regions, each with its own time history,
# and wrote ``Even newspaper reports present contradictory information.''
# Those Hoosiers! Such a flighty and changeable people!
# Fortunately, most of the complexity occurred before our cutoff date of 1970.
# Other than Indianapolis, the Indiana place names are so nondescript
# that they would be ambiguous if we left them at the `America' level.
# From Paul Eggert (2005-08-16):
# From Nathan Stratton Treadway (2006-03-30):
# From Deborah Goldsmith (2006-01-18):
# From Paul Eggert (2006-01-20):
# It says "DOT is relocating the time zone boundary in Indiana to move Starke,
# Pulaski, Knox, Daviess, Martin, Pike, Dubois, and Perry Counties from the
# Eastern Time Zone to the Central Time Zone.... The effective date of
# this rule is 2:OO
a.m. EST Sunday, April 2, 2006, which is the
# changeover date from standard time to Daylight Saving Time."
# Strictly speaking, this means the affected counties will change their
# clocks twice that night, but this obviously is in error. The intent
# is that 01:59:59 EST be followed by 02:00:00 CDT.
# From Gwillim Law (2007-02-10):
# The Associated Press has been reporting that Pulaski County, Indiana is
# going to switch from Central to Eastern Time on March 11, 2007....
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Indianapolis 1941 only - Jun 22 2:00 1:00 D
Rule Indianapolis 1941 1954 - Sep lastSun 2:00 0 S
Rule Indianapolis 1946 1954 - Apr lastSun 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-6:00 Indianapolis C%sT 1942
-6:00 Indianapolis C%sT 1955 Apr 24 2:00
-5:00 - EST 1957 Sep 29 2:00
-6:00 - CST 1958 Apr 27 2:00
# Eastern Crawford County, Indiana, left its clocks alone in 1974,
# as well as from 1976 through 2005.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Marengo 1951 only - Apr lastSun 2:00 1:00 D
Rule Marengo 1951 only - Sep lastSun 2:00 0 S
Rule Marengo 1954 1960 - Apr lastSun 2:00 1:00 D
Rule Marengo 1954 1960 - Sep lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-6:00 Marengo C%sT 1961 Apr 30 2:00
-5:00 US E%sT 1974 Jan 6 2:00
-6:00 1:00 CDT 1974 Oct 27 2:00
# Daviess, Dubois, Knox, and Martin Counties, Indiana,
# switched from eastern to central time in April 2006, then switched back
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Vincennes 1946 only - Apr lastSun 2:00 1:00 D
Rule Vincennes 1946 only - Sep lastSun 2:00 0 S
Rule Vincennes 1953 1954 - Apr lastSun 2:00 1:00 D
Rule Vincennes 1953 1959 - Sep lastSun 2:00 0 S
Rule Vincennes 1955 only - May 1 0:00 1:00 D
Rule Vincennes 1956 1963 - Apr lastSun 2:00 1:00 D
Rule Vincennes 1960 only - Oct lastSun 2:00 0 S
Rule Vincennes 1961 only - Sep lastSun 2:00 0 S
Rule Vincennes 1962 1963 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-6:00 Vincennes C%sT 1964 Apr 26 2:00
-5:00 - EST 2006 Apr 2 2:00
-6:00 US C%sT 2007 Nov 4 2:00
# Perry County, Indiana, switched from eastern to central time in April 2006.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Perry 1946 only - Apr lastSun 2:00 1:00 D
Rule Perry 1946 only - Sep lastSun 2:00 0 S
Rule Perry 1953 1954 - Apr lastSun 2:00 1:00 D
Rule Perry 1953 1959 - Sep lastSun 2:00 0 S
Rule Perry 1955 only - May 1 0:00 1:00 D
Rule Perry 1956 1963 - Apr lastSun 2:00 1:00 D
Rule Perry 1960 only - Oct lastSun 2:00 0 S
Rule Perry 1961 only - Sep lastSun 2:00 0 S
Rule Perry 1962 1963 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-6:00 Perry C%sT 1964 Apr 26 2:00
-5:00 - EST 2006 Apr 2 2:00
# Pike County, Indiana moved from central to eastern time in 1977,
# then switched back in 2006, then switched back again in 2007.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Pike 1955 only - May 1 0:00 1:00 D
Rule Pike 1955 1960 - Sep lastSun 2:00 0 S
Rule Pike 1956 1964 - Apr lastSun 2:00 1:00 D
Rule Pike 1961 1964 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-6:00 Pike C%sT 1965 Apr 25 2:00
-5:00 - EST 1966 Oct 30 2:00
-6:00 US C%sT 1977 Oct 30 2:00
-5:00 - EST 2006 Apr 2 2:00
-6:00 US C%sT 2007 Nov 4 2:00
# Starke County, Indiana moved from central to eastern time in 1991,
# then switched back in 2006.
# From Arthur David Olson (1991-10-28):
# An article on page A3 of the Sunday, 1991-10-27 Washington Post
# notes that Starke County switched from Central time to Eastern time as of
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Starke 1947 1961 - Apr lastSun 2:00 1:00 D
Rule Starke 1947 1954 - Sep lastSun 2:00 0 S
Rule Starke 1955 1956 - Oct lastSun 2:00 0 S
Rule Starke 1957 1958 - Sep lastSun 2:00 0 S
Rule Starke 1959 1961 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-6:00 Starke C%sT 1962 Apr 29 2:00
-5:00 - EST 1963 Oct 27 2:00
-6:00 US C%sT 1991 Oct 27 2:00
-5:00 - EST 2006 Apr 2 2:00
# Pulaski County, Indiana, switched from eastern to central time in
# April 2006 and then switched back in March 2007.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Pulaski 1946 1960 - Apr lastSun 2:00 1:00 D
Rule Pulaski 1946 1954 - Sep lastSun 2:00 0 S
Rule Pulaski 1955 1956 - Oct lastSun 2:00 0 S
Rule Pulaski 1957 1960 - Sep lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-6:00 Pulaski C%sT 1961 Apr 30 2:00
-5:00 - EST 2006 Apr 2 2:00
-6:00 US C%sT 2007 Mar 11 2:00
# Switzerland County, Indiana, did not observe DST from 1973 through 2005.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-6:00 US C%sT 1954 Apr 25 2:00
# Part of Kentucky left its clocks alone in 1974.
# This also includes Clark, Floyd, and Harrison counties in Indiana.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Louisville 1921 only - May 1 2:00 1:00 D
Rule Louisville 1921 only - Sep 1 2:00 0 S
Rule Louisville 1941 1961 - Apr lastSun 2:00 1:00 D
Rule Louisville 1941 only - Sep lastSun 2:00 0 S
Rule Louisville 1946 only - Jun 2 2:00 0 S
Rule Louisville 1950 1955 - Sep lastSun 2:00 0 S
Rule Louisville 1956 1960 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-6:00 Louisville C%sT 1942
-6:00 Louisville C%sT 1961 Jul 23 2:00
-5:00 US E%sT 1974 Jan 6 2:00
-6:00 1:00 CDT 1974 Oct 27 2:00
# </a> (1999-01-29) via WKYM-101.7:
# Clinton County has joined Wayne County in asking the DoT to change from
# the Central to the Eastern time zone.... The Wayne County government made
# the same request in December. And while Russell County officials have not
# taken action, the majority of respondents to a poll conducted there in
# August indicated they would like to change to "fast time" also.
# The three Lake Cumberland counties are the farthest east of any
U.S.# location in the Central time zone.
# From Rich Wales (2000-08-29):
# After prolonged debate, and despite continuing deep differences of opinion,
# Wayne County (central Kentucky) is switching from Central (-0600) to Eastern
# (-0500) time. They won't "fall back" this year. See Sara Shipley,
# The difference an hour makes, Nando Times (2000-08-29 15:33 -0400).
# From Paul Eggert (2001-07-16):
# The final rule was published in the
# Federal Register 65, 160 (2000-08-17), page 50154-50158.
-6:00 US C%sT 2000 Oct 29 2:00
# From Rives McDow (2000-08-30):
# Here ... are all the changes in the US since 1985.
# Kearny County, KS (put all of county on central;
# previously split between MST and CST) ... 1990-10
# Starke County, IN (from CST to EST) ... 1991-10
# Oliver County, ND (from MST to CST) ... 1992-10
# West Wendover, NV (from PST TO MST) ... 1999-10
# Wayne County, KY (from CST to EST) ... 2000-10
# From Paul Eggert (2001-07-17):
# We don't know where the line used to be within Kearny County, KS,
# so omit that change for now.
# West Wendover, NV officially switched from Pacific to mountain time on
# Federal Register 64, 203 (1999-10-21), page 56705-56707.
# However, the Federal Register says that West Wendover already operated
# on mountain time, and the rule merely made this official;
# hence a separate tz entry is not needed.
# From Bob Devine (1988-01-28):
# Michigan didn't observe DST from 1968 to 1973.
# From Paul Eggert (1999-03-31):
# Shanks writes that Michigan started using standard time on 1885-09-18,
# but Howse writes (pp 124-125, referring to Popular Astronomy, 1901-01)
# local time until 1900 when the City Council decreed that clocks should
# be put back twenty-eight minutes to Central Standard Time. Half the
# city obeyed, half refused. After considerable debate, the decision
# was rescinded and the city reverted to Sun time. A derisive offer to
# erect a sundial in front of the city hall was referred to the
# Committee on Sewers. Then, in 1905, Central time was adopted
# This story is too entertaining to be false, so go with Howse over Shanks.
# From Paul Eggert (2001-03-06):
# Garland (1927) writes ``Cleveland and Detroit advanced their clocks
# one hour in 1914.'' This change is not in Shanks. We have no more
# info, so omit this for now.
# Most of Michigan observed DST from 1973 on, but was a bit late in 1975.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Detroit 1948 only - Apr lastSun 2:00 1:00 D
Rule Detroit 1948 only - Sep lastSun 2:00 0 S
Rule Detroit 1967 only - Jun 14 2:00 1:00 D
Rule Detroit 1967 only - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-6:00 - CST 1915 May 15 2:00
-5:00 - EST 1975 Apr 27 2:00
# Dickinson, Gogebic, Iron, and Menominee Counties, Michigan,
# switched from EST to
CST/CDT in 1973.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER
Rule Menominee 1946 only - Apr lastSun 2:00 1:00 D
Rule Menominee 1946 only - Sep lastSun 2:00 0 S
Rule Menominee 1966 only - Apr lastSun 2:00 1:00 D
Rule Menominee 1966 only - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-6:00 Menominee C%sT 1969 Apr 27 2:00
-5:00 - EST 1973 Apr 29 2:00
# administered by the US Fish and Wildlife Service
# claimed by US under the provisions of the 1856 Guano Islands Act
# occupied 1857/1900 by the Navassa Phosphate Co
# US lighthouse 1917/1996-09
# see Mark Fineman, ``An Isle Rich in Guano and Discord'',
# _Los Angeles Times_ (1998-11-10), A1, A10; it cites
# Jimmy Skaggs, _The Great Guano Rush_ (1994).
################################################################################
# From Paul Eggert (2006-03-22):
# A good source for time zone historical data outside the
U.S. is
# Thomas G. Shanks and Rique Pottenger, The International Atlas (6th edition),
# San Diego: ACS Publications, Inc. (2003).
# Gwillim Law writes that a good source
# for recent time zone data is the International Air Transport
# Association's Standard Schedules Information Manual (IATA SSIM),
# published semiannually. Law sent in several helpful summaries
# of the IATA's data after 1990.
# Except where otherwise noted, Shanks & Pottenger is the source for
# entries through 1990, and IATA SSIM is the source for entries afterwards.
# Other sources occasionally used include:
# Edward W. Whitman, World Time Differences,
# Whitman Publishing Co, 2 Niagara Av, Ealing, London (undated),
# which I found in the UCLA library.
# William Willett, The Waste of Daylight, 19th edition
# See the `europe' file for Greenland.
# From Alain LaBont<e'> (1994-11-14):
# I post here the time zone abbreviations standardized in Canada
# UTC Standard time Daylight savings time
# offset French English French English
# HN: Heure Normale ST: Standard Time
# HA: Heure Avanc<e'>e DT: Daylight saving Time
# A: de l'Atlantique Atlantic
# P: du Pacifique Pacific
# From Paul Eggert (1994-11-22):
# Alas, this sort of thing must be handled by localization software.
# Unless otherwise specified, the data for Canada are all from Shanks
# From Chris Walton (2006-04-01, 2006-04-25, 2006-06-26, 2007-01-31,
# The British Columbia government announced yesterday that it will
# adjust daylight savings next year to align with changes in the
#
U.S. and the rest of Canada....
# Daylight saving time will be extended by four weeks starting in 2007....
# [For New Brunswick] the new legislation dictates that the time change is to
# be done at 02:00 instead of 00:01.
# Manitoba has traditionally changed the clock every fall at 03:00.
# As of 2006, the transition is to take place one hour earlier at 02:00.
# [Alberta, Ontario, Quebec] will follow US rules.
#
P.E.I. will follow US rules....
# Province of Newfoundland and Labrador....
#
N.W.T. will follow US rules. Whoever maintains the government web site
# does not seem to believe in bookmarks. To see the news release, click the
# following link and search for "Daylight Savings Time Change". Press the
# "Daylight Savings Time Change" link; it will fire off a popup using
# An amendment to the Interpretation Act was registered on February 19/2007....
# From Paul Eggert (2006-04-25):
# H. David Matthews and Mary Vincent's map
# "It's about TIME", _Canadian Geographic_ (September-October 1998)
# </a> contains detailed boundaries for regions observing nonstandard
# time and daylight saving time arrangements in Canada circa 1998.
# INMS, the Institute for National Measurement Standards in Ottawa, has <a
# information about standard and daylight saving time zones in Canada.
# </a> (updated periodically).
# Its unofficial information is often taken from Matthews and Vincent.
# From Paul Eggert (2006-06-27):
# For now, assume all of DST-observing Canada will fall into line with the
# From Chris Walton (2011-12-01)
# In the first of Tammy Hardwick's articles
# she quotes the Friday November 1/1918 edition of the Creston Review.
# The quote includes these two statements:
# 'Sunday the CPR went back to the old system of time...'
# '... The daylight saving scheme was dropped all over Canada at the same time,'
# These statements refer to a transition from daylight time to standard time
# that occurred nationally on Sunday October 27/1918. This transition was
# also documented in the Saturday October 26/1918 edition of the Toronto Star.
# In light of that evidence, we alter the date from the earlier believed
# Oct 31, to Oct 27, 1918 (and Sunday is a more likely transition day
# than Thursday) in all Canadian rulesets.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Canada 1918 only - Apr 14 2:00 1:00 D
Rule Canada 1918 only - Oct 27 2:00 0 S
Rule Canada 1942 only - Feb 9 2:00 1:00 W # War
Rule Canada 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule Canada 1945 only - Sep 30 2:00 0 S
Rule Canada 1974 1986 - Apr lastSun 2:00 1:00 D
Rule Canada 1974 2006 - Oct lastSun 2:00 0 S
Rule Canada 1987 2006 - Apr Sun>=1 2:00 1:00 D
Rule Canada 2007 max - Mar Sun>=8 2:00 1:00 D
Rule Canada 2007 max - Nov Sun>=1 2:00 0 S
# Newfoundland and Labrador
# From Paul Eggert (2000-10-02):
# Matthews and Vincent (1998) write that Labrador should use
NST/NDT,
# but the only part of Labrador that follows the rules is the
# southeast corner, including Port Hope Simpson and Mary's Harbour,
# but excluding, say, Black Tickle.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule StJohns 1917 only - Apr 8 2:00 1:00 D
Rule StJohns 1917 only - Sep 17 2:00 0 S
# Whitman gives 1919 Apr 5 and 1920 Apr 5; go with Shanks & Pottenger.
Rule StJohns 1919 only - May 5 23:00 1:00 D
Rule StJohns 1919 only - Aug 12 23:00 0 S
# For 1931-1935 Whitman gives Apr same date; go with Shanks & Pottenger.
Rule StJohns 1920 1935 - May Sun>=1 23:00 1:00 D
Rule StJohns 1920 1935 - Oct lastSun 23:00 0 S
# For 1936-1941 Whitman gives May Sun>=8 and Oct Sun>=1; go with Shanks &
Rule StJohns 1936 1941 - May Mon>=9 0:00 1:00 D
Rule StJohns 1936 1941 - Oct Mon>=2 0:00 0 S
# Whitman gives the following transitions:
# 1942 03-01/12-31, 1943 05-30/09-05, 1944 07-10/09-02, 1945 01-01/10-07
# but go with Shanks & Pottenger and assume they used Canadian rules.
# For 1946-9 Whitman gives May 5,4,9,1 - Oct 1,5,3,2, and for 1950 he gives
# Apr 30 - Sep 24; go with Shanks & Pottenger.
Rule StJohns 1946 1950 - May Sun>=8 2:00 1:00 D
Rule StJohns 1946 1950 - Oct Sun>=2 2:00 0 S
Rule StJohns 1951 1986 - Apr lastSun 2:00 1:00 D
Rule StJohns 1951 1959 - Sep lastSun 2:00 0 S
Rule StJohns 1960 1986 - Oct lastSun 2:00 0 S
# From Paul Eggert (2000-10-02):
# INMS (2000-09-12) says that, since 1988 at least, Newfoundland switches
# at 00:01 local time. For now, assume it started in 1987.
# From Michael Pelley (2011-09-12):
# We received today, Monday, September 12, 2011, notification that the
# changes to the Newfoundland Standard Time Act have been proclaimed.
# The change in the Act stipulates that the change from Daylight Savings
# Time to Standard Time and from Standard Time to Daylight Savings Time
# MICHAEL PELLEY | Manager of Enterprise Architecture - Solution Delivery
# Office of the Chief Information Officer
# Government of Newfoundland & Labrador
Rule StJohns 1987 only - Apr Sun>=1 0:01 1:00 D
Rule StJohns 1987 2006 - Oct lastSun 0:01 0 S
Rule StJohns 1988 only - Apr Sun>=1 0:01 2:00 DD
Rule StJohns 1989 2006 - Apr Sun>=1 0:01 1:00 D
Rule StJohns 2007 2011 - Mar Sun>=8 0:01 1:00 D
Rule StJohns 2007 2010 - Nov Sun>=1 0:01 0 S
# St John's has an apostrophe, but Posix file names can't have apostrophes.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-3:30:52 StJohns N%sT 1918
-3:30:52 Canada N%sT 1919
-3:30:52 StJohns N%sT 1935 Mar 30
-3:30 StJohns N%sT 1942 May 11
-3:30 StJohns N%sT 2011 Nov
# The name `Happy Valley-Goose Bay' is too long; use `Goose Bay'.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-3:30:52 Canada N%sT 1919
-3:30:52 - NST 1935 Mar 30
-3:30 StJohns N%sT 1942 May 11
-3:30 StJohns N%sT 1966 Mar 15 2:00
-4:00 StJohns A%sT 2011 Nov
# west Labrador, Nova Scotia, Prince Edward I
# From Paul Eggert (2006-03-22):
# Shanks & Pottenger write that since 1970 most of this region has been like
# Halifax. Many locales did not observe peacetime DST until 1972;
# Glace Bay, NS is the largest that we know of.
# Shanks & Pottenger also write that Liverpool, NS was the only town
# in Canada to observe DST in 1971 but not 1970; for now we'll assume
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Halifax 1916 only - Apr 1 0:00 1:00 D
Rule Halifax 1916 only - Oct 1 0:00 0 S
Rule Halifax 1920 only - May 9 0:00 1:00 D
Rule Halifax 1920 only - Aug 29 0:00 0 S
Rule Halifax 1921 only - May 6 0:00 1:00 D
Rule Halifax 1921 1922 - Sep 5 0:00 0 S
Rule Halifax 1922 only - Apr 30 0:00 1:00 D
Rule Halifax 1923 1925 - May Sun>=1 0:00 1:00 D
Rule Halifax 1923 only - Sep 4 0:00 0 S
Rule Halifax 1924 only - Sep 15 0:00 0 S
Rule Halifax 1925 only - Sep 28 0:00 0 S
Rule Halifax 1926 only - May 16 0:00 1:00 D
Rule Halifax 1926 only - Sep 13 0:00 0 S
Rule Halifax 1927 only - May 1 0:00 1:00 D
Rule Halifax 1927 only - Sep 26 0:00 0 S
Rule Halifax 1928 1931 - May Sun>=8 0:00 1:00 D
Rule Halifax 1928 only - Sep 9 0:00 0 S
Rule Halifax 1929 only - Sep 3 0:00 0 S
Rule Halifax 1930 only - Sep 15 0:00 0 S
Rule Halifax 1931 1932 - Sep Mon>=24 0:00 0 S
Rule Halifax 1932 only - May 1 0:00 1:00 D
Rule Halifax 1933 only - Apr 30 0:00 1:00 D
Rule Halifax 1933 only - Oct 2 0:00 0 S
Rule Halifax 1934 only - May 20 0:00 1:00 D
Rule Halifax 1934 only - Sep 16 0:00 0 S
Rule Halifax 1935 only - Jun 2 0:00 1:00 D
Rule Halifax 1935 only - Sep 30 0:00 0 S
Rule Halifax 1936 only - Jun 1 0:00 1:00 D
Rule Halifax 1936 only - Sep 14 0:00 0 S
Rule Halifax 1937 1938 - May Sun>=1 0:00 1:00 D
Rule Halifax 1937 1941 - Sep Mon>=24 0:00 0 S
Rule Halifax 1939 only - May 28 0:00 1:00 D
Rule Halifax 1940 1941 - May Sun>=1 0:00 1:00 D
Rule Halifax 1946 1949 - Apr lastSun 2:00 1:00 D
Rule Halifax 1946 1949 - Sep lastSun 2:00 0 S
Rule Halifax 1951 1954 - Apr lastSun 2:00 1:00 D
Rule Halifax 1951 1954 - Sep lastSun 2:00 0 S
Rule Halifax 1956 1959 - Apr lastSun 2:00 1:00 D
Rule Halifax 1956 1959 - Sep lastSun 2:00 0 S
Rule Halifax 1962 1973 - Apr lastSun 2:00 1:00 D
Rule Halifax 1962 1973 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:00 Halifax A%sT 1942 Feb 9 2:00s
# From Paul Eggert (2007-01-31):
# says they changed at 00:01 through 2006, and
# clear that this was the case since at least 1993.
# For now, assume it started in 1993.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Moncton 1933 1935 - Jun Sun>=8 1:00 1:00 D
Rule Moncton 1933 1935 - Sep Sun>=8 1:00 0 S
Rule Moncton 1936 1938 - Jun Sun>=1 1:00 1:00 D
Rule Moncton 1936 1938 - Sep Sun>=1 1:00 0 S
Rule Moncton 1939 only - May 27 1:00 1:00 D
Rule Moncton 1939 1941 - Sep Sat>=21 1:00 0 S
Rule Moncton 1940 only - May 19 1:00 1:00 D
Rule Moncton 1941 only - May 4 1:00 1:00 D
Rule Moncton 1946 1972 - Apr lastSun 2:00 1:00 D
Rule Moncton 1946 1956 - Sep lastSun 2:00 0 S
Rule Moncton 1957 1972 - Oct lastSun 2:00 0 S
Rule Moncton 1993 2006 - Apr Sun>=1 0:01 1:00 D
Rule Moncton 1993 2006 - Oct lastSun 0:01 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# From Paul Eggert (2006-07-09):
# Shanks & Pottenger write that since 1970 most of Quebec has been
# From Paul Eggert (2006-06-27):
# Matthews and Vincent (1998) also write that Quebec east of the -63
# meridian is supposed to observe AST, but residents as far east as
# Natashquan use
EST/EDT, and residents east of Natashquan use AST.
# In "Official time in Quebec" the Quebec department of justice writes in
# that "The residents of the Municipality of the
# Cote-Nord-du-Golfe-Saint-Laurent and the municipalities of Saint-Augustin,
# Bonne-Esperance and Blanc-Sablon apply the Official Time Act as it is
# written and use Atlantic standard time all year round. The same applies to
# the residents of the Native facilities along the lower North Shore."
# says this common practice was codified into law as of 2007.
# For lack of better info, guess this practice began around 1970, contra to
# Shanks & Pottenger who have this region observing
AST/ADT.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Mont 1917 only - Mar 25 2:00 1:00 D
Rule Mont 1917 only - Apr 24 0:00 0 S
Rule Mont 1919 only - Mar 31 2:30 1:00 D
Rule Mont 1919 only - Oct 25 2:30 0 S
Rule Mont 1920 only - May 2 2:30 1:00 D
Rule Mont 1920 1922 - Oct Sun>=1 2:30 0 S
Rule Mont 1921 only - May 1 2:00 1:00 D
Rule Mont 1922 only - Apr 30 2:00 1:00 D
Rule Mont 1924 only - May 17 2:00 1:00 D
Rule Mont 1924 1926 - Sep lastSun 2:30 0 S
Rule Mont 1925 1926 - May Sun>=1 2:00 1:00 D
# The 1927-to-1937 rules can be expressed more simply as
# Rule Mont 1927 1937 - Apr lastSat 24:00 1:00 D
# Rule Mont 1927 1937 - Sep lastSat 24:00 0 S
# The rules below avoid use of 24:00
# (which pre-1998 versions of zic cannot handle).
Rule Mont 1927 only - May 1 0:00 1:00 D
Rule Mont 1927 1932 - Sep lastSun 0:00 0 S
Rule Mont 1928 1931 - Apr lastSun 0:00 1:00 D
Rule Mont 1932 only - May 1 0:00 1:00 D
Rule Mont 1933 1940 - Apr lastSun 0:00 1:00 D
Rule Mont 1933 only - Oct 1 0:00 0 S
Rule Mont 1934 1939 - Sep lastSun 0:00 0 S
Rule Mont 1946 1973 - Apr lastSun 2:00 1:00 D
Rule Mont 1945 1948 - Sep lastSun 2:00 0 S
Rule Mont 1949 1950 - Oct lastSun 2:00 0 S
Rule Mont 1951 1956 - Sep lastSun 2:00 0 S
Rule Mont 1957 1973 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-5:00 Mont E%sT 1942 Feb 9 2:00s
# From Paul Eggert (2006-07-09):
# Shanks & Pottenger write that since 1970 most of Ontario has been like
# Thunder Bay skipped DST in 1973.
# Many smaller locales did not observe peacetime DST until 1974;
# Nipigon (EST) and Rainy River (CST) are the largest that we know of.
# Far west Ontario is like Winnipeg; far east Quebec is like Halifax.
# From Mark Brader (2003-07-26):
# [According to the Toronto Star] Orillia, Ontario, adopted DST
# effective Saturday, 1912-06-22, 22:00; the article mentions that
# Port Arthur (now part of Thunder Bay, Ontario) as well as Moose Jaw
# have already done so. In Orillia DST was to run until Saturday,
# 1912-08-31 (no time mentioned), but it was met with considerable
# hostility from certain segments of the public, and was revoked after
# only two weeks -- I copied it as Saturday, 1912-07-07, 22:00, but
# presumably that should be -07-06. (1912-06-19, -07-12; also letters
# Kenora, Ontario, was to abandon DST on 1914-06-01 (-05-21).
# From Paul Eggert (1997-10-17):
# Mark Brader writes that an article in the 1997-10-14 Toronto Star
# says that Atikokan, Ontario currently does not observe DST,
# but will vote on 11-10 whether to use
EST/EDT.
# He also writes that the
# Ontario Time Act (1990, Chapter T.9)
# says that Ontario east of 90W uses
EST/EDT, and west of 90W uses
CST/CDT.
# Officially Atikokan is therefore on
CST/CDT, and most likely this report
# concerns a non-official time observed as a matter of local practice.
# From Paul Eggert (2000-10-02):
# Matthews and Vincent (1998) write that Atikokan, Pickle Lake, and
# New Osnaburgh observe CST all year, that Big Trout Lake observes
# violation of the official Ontario rules.
# From Paul Eggert (2006-07-09):
# Chris Walton (2006-07-06) mentioned an article by Stephanie MacLellan in the
# 2005-07-21 Chronicle-Journal, which said:
# The clocks in Atikokan stay set on standard time year-round.
# This means they spend about half the time on central time and
# the other half on eastern time.
# For the most part, the system works, Mayor Dennis Brown said.
# "The majority of businesses in Atikokan deal more with Eastern
# Canada, but there are some that deal with Western Canada," he
# said. "I don't see any changes happening here."
# Walton also writes "Supposedly Pickle Lake and Mishkeegogamang
# [New Osnaburgh] follow the same practice."
# From Garry McKinnon (2006-07-14) via Chris Walton:
# I chatted with a member of my board who has an outstanding memory
# and a long history in Atikokan (and in the telecom industry) and he
# can say for certain that Atikokan has been practicing the current
# time keeping since 1952, at least.
# From Paul Eggert (2006-07-17):
# Shanks & Pottenger say that Atikokan has agreed with Rainy River
# ever since standard time was introduced, but the information from
# McKinnon sounds more authoritative. For now, assume that Atikokan
# switched to EST immediately after WWII era daylight saving time
# entry since our cutoff date of 1970, so we can move
# From Mark Brader (2010-03-06):
# Currently the database has:
# # From Paul Eggert (2006-07-09):
# # Shanks & Pottenger write that since 1970 most of Ontario has been like
# # Thunder Bay skipped DST in 1973.
# # Many smaller locales did not observe peacetime DST until 1974;
# # Nipigon (EST) and Rainy River (CST) are the largest that we know of.
# In the (Toronto) Globe and Mail for Saturday, 1955-09-24, in the bottom
# right corner of page 1, it says that Toronto will return to standard
# time at 2 am Sunday morning (which agrees with the database), and that:
# The one-hour setback will go into effect throughout most of Ontario,
# except in areas like Windsor which remains on standard time all year.
# Windsor is, of course, a lot larger than Nipigon.
# I only came across this incidentally. I don't know if Windsor began
# observing DST when Detroit did, or in 1974, or on some other date.
# By the way, the article continues by noting that:
# Some cities in the United States have pushed the deadline back
# three weeks and will change over from daylight saving in October.
# From Arthur David Olson (2010-07-17):
# "Standard Time and Time Zones in Canada" appeared in
# The Journal of The Royal Astronomical Society of Canada,
# volume 26, number 2 (February 1932) and, as of 2010-07-17,
# It includes the text below (starting on page 57):
# A list of the places in Canada using daylight saving time would
# require yearly revision. From information kindly furnished by
# the provincial governments and by the postmasters in many cities
# and towns, it is found that the following places used daylight sav-
# ing in 1930. The information for the province of Quebec is definite,
# for the other provinces only approximate:
# Province Daylight saving time used
# Prince Edward Island Not used.
# Nova Scotia In Halifax only.
# New Brunswick In St. John only.
# Quebec In the following places:
# St. Lambert Cap de la Madeleine
# Longueuil Greenfield Park
# Chambly-Canton Beaulieu
# St. Theophile Buckingham
# Ontario Used generally in the cities and towns along
# the southerly part of the province. Not
# used in the northwesterlhy part.
# Saskatchewan In Regina only.
# British Columbia Not used.
# With some exceptions, the use of daylight saving may be said to be limited
# to those cities and towns lying between Quebec city and Windsor, Ont.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Toronto 1919 only - Mar 30 23:30 1:00 D
Rule Toronto 1919 only - Oct 26 0:00 0 S
Rule Toronto 1920 only - May 2 2:00 1:00 D
Rule Toronto 1920 only - Sep 26 0:00 0 S
Rule Toronto 1921 only - May 15 2:00 1:00 D
Rule Toronto 1921 only - Sep 15 2:00 0 S
Rule Toronto 1922 1923 - May Sun>=8 2:00 1:00 D
# Shanks & Pottenger say 1923-09-19; assume it's a typo and that "-16"
Rule Toronto 1922 1926 - Sep Sun>=15 2:00 0 S
Rule Toronto 1924 1927 - May Sun>=1 2:00 1:00 D
# The 1927-to-1939 rules can be expressed more simply as
# Rule Toronto 1927 1937 - Sep Sun>=25 2:00 0 S
# Rule Toronto 1928 1937 - Apr Sun>=25 2:00 1:00 D
# Rule Toronto 1938 1940 - Apr lastSun 2:00 1:00 D
# Rule Toronto 1938 1939 - Sep lastSun 2:00 0 S
# The rules below avoid use of Sun>=25
# (which pre-2004 versions of zic cannot handle).
Rule Toronto 1927 1932 - Sep lastSun 2:00 0 S
Rule Toronto 1928 1931 - Apr lastSun 2:00 1:00 D
Rule Toronto 1932 only - May 1 2:00 1:00 D
Rule Toronto 1933 1940 - Apr lastSun 2:00 1:00 D
Rule Toronto 1933 only - Oct 1 2:00 0 S
Rule Toronto 1934 1939 - Sep lastSun 2:00 0 S
Rule Toronto 1945 1946 - Sep lastSun 2:00 0 S
Rule Toronto 1946 only - Apr lastSun 2:00 1:00 D
Rule Toronto 1947 1949 - Apr lastSun 0:00 1:00 D
Rule Toronto 1947 1948 - Sep lastSun 0:00 0 S
Rule Toronto 1949 only - Nov lastSun 0:00 0 S
Rule Toronto 1950 1973 - Apr lastSun 2:00 1:00 D
Rule Toronto 1950 only - Nov lastSun 2:00 0 S
Rule Toronto 1951 1956 - Sep lastSun 2:00 0 S
# Shanks & Pottenger say Toronto ended DST a week early in 1971,
# namely on 1971-10-24, but Mark Brader wrote (2003-05-31) that this
# is wrong, and that he had confirmed it by checking the 1971-10-30
# Toronto Star, which said that DST was ending 1971-10-31 as usual.
Rule Toronto 1957 1973 - Oct lastSun 2:00 0 S
# From Paul Eggert (2003-07-27):
# Willett (1914-03) writes (p. 17) "In the Cities of Fort William, and
# Port Arthur, Ontario, the principle of the Bill has been in
# operation for the past three years, and in the City of Moose Jaw,
# Saskatchewan, for one year."
# Thunder Bay Museum (2003-11-12):
# There is some suggestion, however, that, by-law or not, daylight
# savings time was being practiced in Fort William and Port Arthur
# before 1909.... [I]n 1910, the line between the Eastern and Central
# Time Zones was permanently moved about two hundred miles west to
# include the Thunder Bay area.... When Canada adopted daylight
# savings time in 1916, Fort William and Port Arthur, having done so
# already, did not change their clocks.... During the Second World
# War,... [t]he cities agreed to implement DST during the summer
# months for the remainder of the war years.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-5:00 Toronto E%sT 1942 Feb 9 2:00s
-5:00 Canada E%sT 1940 Sep 29
-5:00 1:00 EDT 1942 Feb 9 2:00s
-6:00 Canada C%sT 1940 Sep 29
-6:00 1:00 CDT 1942 Feb 9 2:00s
-6:00 Canada C%sT 1940 Sep 29
-6:00 1:00 CDT 1942 Feb 9 2:00s
-6:00 Canada C%sT 1945 Sep 30 2:00
# From Rob Douglas (2006-04-06):
# the old Manitoba Time Act - as amended by Bill 2, assented to
# March 27, 1987 ... said ...
# "between two o'clock Central Standard Time in the morning of
# the first Sunday of April of each year and two o'clock Central
# Standard Time in the morning of the last Sunday of October next
# following, one hour in advance of Central Standard Time."...
# I believe that the English legislation [of the old time act] had =
# been assented to (March 22, 1967)....
# Also, as far as I can tell, there was no order-in-council varying
# the time of Daylight Saving Time for 2005 and so the provisions of
# the 1987 version would apply - the changeover was at 2:00 Central
# Standard Time (
i.e. not until 3:00 Central Daylight Time).
# From Paul Eggert (2006-04-10):
# Shanks & Pottenger say Manitoba switched at 02:00 (not 02:00s)
# starting 1966. Since 02:00s is clearly correct for 1967 on, assume
# it was also 02:00s in 1966.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Winn 1916 only - Apr 23 0:00 1:00 D
Rule Winn 1916 only - Sep 17 0:00 0 S
Rule Winn 1918 only - Apr 14 2:00 1:00 D
Rule Winn 1918 only - Oct 27 2:00 0 S
Rule Winn 1937 only - May 16 2:00 1:00 D
Rule Winn 1937 only - Sep 26 2:00 0 S
Rule Winn 1942 only - Feb 9 2:00 1:00 W # War
Rule Winn 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule Winn 1945 only - Sep lastSun 2:00 0 S
Rule Winn 1946 only - May 12 2:00 1:00 D
Rule Winn 1946 only - Oct 13 2:00 0 S
Rule Winn 1947 1949 - Apr lastSun 2:00 1:00 D
Rule Winn 1947 1949 - Sep lastSun 2:00 0 S
Rule Winn 1950 only - May 1 2:00 1:00 D
Rule Winn 1950 only - Sep 30 2:00 0 S
Rule Winn 1951 1960 - Apr lastSun 2:00 1:00 D
Rule Winn 1951 1958 - Sep lastSun 2:00 0 S
Rule Winn 1959 only - Oct lastSun 2:00 0 S
Rule Winn 1960 only - Sep lastSun 2:00 0 S
Rule Winn 1963 only - Apr lastSun 2:00 1:00 D
Rule Winn 1963 only - Sep 22 2:00 0 S
Rule Winn 1966 1986 - Apr lastSun 2:00s 1:00 D
Rule Winn 1966 2005 - Oct lastSun 2:00s 0 S
Rule Winn 1987 2005 - Apr Sun>=1 2:00s 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# From Mark Brader (2003-07-26):
# The first actual adoption of DST in Canada was at the municipal
# level. As the [Toronto] Star put it (1912-06-07), "While people
# elsewhere have long been talking of legislation to save daylight,
# the city of Moose Jaw [Saskatchewan] has acted on its own hook."
# DST in Moose Jaw began on Saturday, 1912-06-01 (no time mentioned:
# presumably late evening, as below), and would run until "the end of
# the summer". The discrepancy between municipal time and railroad
# From Paul Eggert (2003-07-27):
# Willett (1914-03) notes that DST "has been in operation ... in the
# City of Moose Jaw, Saskatchewan, for one year."
# From Paul Eggert (2006-03-22):
# Shanks & Pottenger say that since 1970 this region has mostly been as Regina.
# Some western towns (
e.g. Swift Current) switched from
MST/MDT to CST in 1972.
# Other western towns (
e.g. Lloydminster) are like Edmonton.
# Matthews and Vincent (1998) write that Denare Beach and Creighton
# are like Winnipeg, in violation of Saskatchewan law.
# From W. Jones (1992-11-06):
# The. . .below is based on information I got from our law library, the
# provincial archives, and the provincial Community Services department.
# A precise history would require digging through newspaper archives, and
# since you didn't say what you wanted, I didn't bother.
# Saskatchewan is split by a time zone meridian (105W) and over the years
# the boundary became pretty ragged as communities near it reevaluated
# their affiliations in one direction or the other. In 1965 a provincial
# referendum favoured legislating common time practices.
# On 15 April 1966 the Time Act (c. T-14, Revised Statutes of
# Saskatchewan 1978) was proclaimed, and established that the eastern
# part of Saskatchewan would use CST year round, that districts in
# northwest Saskatchewan would by default follow CST but could opt to
# follow Mountain Time rules (thus 1 hour difference in the winter and
# zero in the summer), and that districts in southwest Saskatchewan would
# by default follow MT but could opt to follow CST.
# It took a few years for the dust to settle (I know one story of a town
# on one time zone having its school in another, such that a mom had to
# serve her family lunch in two shifts), but presently it seems that only
# a few towns on the border with Alberta (
e.g. Lloydminster) follow MT
# rules any more; all other districts appear to have used CST year round
# since sometime in the 1960s.
# From Chris Walton (2006-06-26):
# The Saskatchewan time act which was last updated in 1996 is about 30 pages
# long and rather painful to read.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Regina 1918 only - Apr 14 2:00 1:00 D
Rule Regina 1918 only - Oct 27 2:00 0 S
Rule Regina 1930 1934 - May Sun>=1 0:00 1:00 D
Rule Regina 1930 1934 - Oct Sun>=1 0:00 0 S
Rule Regina 1937 1941 - Apr Sun>=8 0:00 1:00 D
Rule Regina 1937 only - Oct Sun>=8 0:00 0 S
Rule Regina 1938 only - Oct Sun>=1 0:00 0 S
Rule Regina 1939 1941 - Oct Sun>=8 0:00 0 S
Rule Regina 1942 only - Feb 9 2:00 1:00 W # War
Rule Regina 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule Regina 1945 only - Sep lastSun 2:00 0 S
Rule Regina 1946 only - Apr Sun>=8 2:00 1:00 D
Rule Regina 1946 only - Oct Sun>=8 2:00 0 S
Rule Regina 1947 1957 - Apr lastSun 2:00 1:00 D
Rule Regina 1947 1957 - Sep lastSun 2:00 0 S
Rule Regina 1959 only - Apr lastSun 2:00 1:00 D
Rule Regina 1959 only - Oct lastSun 2:00 0 S
Rule Swift 1957 only - Apr lastSun 2:00 1:00 D
Rule Swift 1957 only - Oct lastSun 2:00 0 S
Rule Swift 1959 1961 - Apr lastSun 2:00 1:00 D
Rule Swift 1959 only - Oct lastSun 2:00 0 S
Rule Swift 1960 1961 - Sep lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-7:00 Regina M%sT 1960 Apr lastSun 2:00
-7:00 Canada M%sT 1946 Apr lastSun 2:00
-7:00 Swift M%sT 1972 Apr lastSun 2:00
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Edm 1918 1919 - Apr Sun>=8 2:00 1:00 D
Rule Edm 1918 only - Oct 27 2:00 0 S
Rule Edm 1919 only - May 27 2:00 0 S
Rule Edm 1920 1923 - Apr lastSun 2:00 1:00 D
Rule Edm 1920 only - Oct lastSun 2:00 0 S
Rule Edm 1921 1923 - Sep lastSun 2:00 0 S
Rule Edm 1942 only - Feb 9 2:00 1:00 W # War
Rule Edm 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule Edm 1945 only - Sep lastSun 2:00 0 S
Rule Edm 1947 only - Apr lastSun 2:00 1:00 D
Rule Edm 1947 only - Sep lastSun 2:00 0 S
Rule Edm 1967 only - Apr lastSun 2:00 1:00 D
Rule Edm 1967 only - Oct lastSun 2:00 0 S
Rule Edm 1969 only - Apr lastSun 2:00 1:00 D
Rule Edm 1969 only - Oct lastSun 2:00 0 S
Rule Edm 1972 1986 - Apr lastSun 2:00 1:00 D
Rule Edm 1972 2006 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# From Paul Eggert (2006-03-22):
# Shanks & Pottenger write that since 1970 most of this region has
# Dawson Creek uses MST. Much of east BC is like Edmonton.
# Matthews and Vincent (1998) write that Creston is like Dawson Creek.
# It seems though that (re: Creston) is not entirely correct:
# From Chris Walton (2011-12-01):
# There are two areas within the Canadian province of British Columbia
# that do not currently observe daylight saving:
# a) The Creston Valley (includes the town of Creston and surrounding area)
# b) The eastern half of the Peace River Regional District
# (includes the cities of Dawson Creek and Fort St. John)
# Earlier this year I stumbled across a detailed article about the time
# keeping history of Creston; it was written by Tammy Hardwick who is the
# manager of the Creston & District Museum. The article was written in May 2009.
# According to the article, Creston has not changed its clocks since June 1918.
#
i.e. Creston has been stuck on UTC-7 for 93 years.
# Dawson Creek, on the other hand, changed its clocks as recently as April 1972.
# Unfortunately the exact date for the time change in June 1918 remains
# unknown and will be difficult to ascertain. I e-mailed Tammy a few months
# ago to ask if Sunday June 2 was a reasonable guess. She said it was just
# as plausible as any other date (in June). She also said that after writing the
# article she had discovered another time change in 1916; this is the subject
# of another article which she wrote in October 2010.
# Here is a summary of the three clock change events in Creston's history:
# 1. 1884 or 1885: adoption of Mountain Standard Time (GMT-7)
# 2. Oct 1916: switch to Pacific Standard Time (GMT-8)
# Exact date in October unknown; Sunday October 1 is a reasonable guess.
# 3. June 1918: switch to Pacific Daylight Time (GMT-7)
# Exact date in June unknown; Sunday June 2 is a reasonable guess.
# On Oct 27/1918 when daylight saving ended in the rest of Canada,
# Creston did not change its clocks.
# During WWII when the Federal Government legislated a mandatory clock change,
# Creston did not oblige.
# There is no guarantee that Creston will remain on Mountain Standard Time
# The subject was debated at least once this year by the town Council.
# During a period WWII, summer time (Daylight saying) was mandatory in Canada.
# In Creston, that was handled by shifting the area to PST (-8:00) then applying
# summer time to cause the offset to be -7:00, the same as it had been before
# the change. It can be argued that the timezone abbreviation during this
# period should be PDT rather than MST, but that doesn't seem important enough
# (to anyone) to further complicate the rules.
# The transition dates (and times) are guesses.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Vanc 1918 only - Apr 14 2:00 1:00 D
Rule Vanc 1918 only - Oct 27 2:00 0 S
Rule Vanc 1942 only - Feb 9 2:00 1:00 W # War
Rule Vanc 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule Vanc 1945 only - Sep 30 2:00 0 S
Rule Vanc 1946 1986 - Apr lastSun 2:00 1:00 D
Rule Vanc 1946 only - Oct 13 2:00 0 S
Rule Vanc 1947 1961 - Sep lastSun 2:00 0 S
Rule Vanc 1962 2006 - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-8:00 Vanc P%sT 1972 Aug 30 2:00
# Northwest Territories, Nunavut, Yukon
# From Paul Eggert (2006-03-22):
# Dawson switched to PST in 1973. Inuvik switched to MST in 1979.
# Mathew Englander (1996-10-07) gives the following refs:
# * 1967. Paragraph 28(34)(g) of the Interpretation Act,
S.C. 1967-68,
# c. 7 defines Yukon standard time as UTC-9. This is still valid;
# see Interpretation Act,
R.S.C. 1985, c. I-21, s. 35(1).
# *
C.O. 1973/214 switched Yukon to PST on 1973-10-28 00:00.
# *
O.I.C. 1980/02 established DST.
# *
O.I.C. 1987/056 changed DST to Apr firstSun 2:00 to Oct lastSun 2:00.
# Shanks & Pottenger say Yukon's 1973-10-28 switch was at 2:00; go
# From Chris Walton (2006-06-26):
# Here is a link to the old daylight saving portion of the interpretation
# act which was last updated in 1987:
# From Rives McDow (1999-09-04):
# Nunavut ... moved ... to incorporate the whole territory into one time zone.
# Nunavut moves to single time zone Oct. 31
# From Antoine Leca (1999-09-06):
# We then need to create a new timezone for the Kitikmeot region of Nunavut
# to differentiate it from the Yellowknife region.
# From Paul Eggert (1999-09-20):
# Basic Facts: The New Territory
# </a> (1999) reports that Pangnirtung operates on eastern time,
# and that Coral Harbour does not observe DST. We don't know when
# Pangnirtung switched to eastern time; we'll guess 1995.
# From Rives McDow (1999-11-08):
# On October 31, when the rest of Nunavut went to Central time,
# Pangnirtung wobbled. Here is the result of their wobble:
# The following businesses and organizations in Pangnirtung use Central Time:
# First Air, Power Corp, Nunavut Construction, Health Center, RCMP,
# Eastern Arctic National Parks, A & D Specialist
# The following businesses and organizations in Pangnirtung use Eastern Time:
# Hamlet office, All other businesses, Both schools, Airport operator
# This has made for an interesting situation there, which warranted the news.
# No one there that I spoke with seems concerned, or has plans to
# change the local methods of keeping time, as it evidently does not
# really interfere with any activities or make things difficult locally.
# They plan to celebrate New Year's turn-over twice, one hour apart,
# so it appears that the situation will last at least that long.
# The Nunavut Intergovernmental Affairs hopes that they will "come to
# their senses", but the locals evidently don't see any problem with
# the current state of affairs.
# From Michaela Rodrigue, writing in the
# Nunatsiaq News (1999-11-19)</a>:
# Clyde River, Pangnirtung and Sanikiluaq now operate with two time zones,
# central - or Nunavut time - for government offices, and eastern time
# for municipal offices and schools.... Igloolik [was similar but then]
# made the switch to central time on Saturday, Nov. 6.
# From Paul Eggert (2000-10-02):
# Matthews and Vincent (1998) say the following, but we lack histories
# for these potential new Zones.
# The Canadian Forces station at Alert uses Eastern Time while the
# handful of residents at the Eureka weather station [in the Central
# zone] skip daylight savings. Baffin Island, which is crossed by the
# Central, Eastern and Atlantic Time zones only uses Eastern Time.
# Gjoa Haven, Taloyoak and Pelly Bay all use Mountain instead of
# Central Time and Southampton Island [in the Central zone] is not
# required to use daylight savings.
# Nunavut now has two time zones
# The Nunavut government would allow its employees in Kugluktuk and
# Cambridge Bay to operate on central time year-round, putting them
# one hour behind the rest of Nunavut for six months during the winter.
# At the end of October the two communities had rebelled against
# Nunavut's unified time zone, refusing to shift to eastern time with
# the rest of the territory for the winter. Cambridge Bay remained on
# central time, while Kugluktuk, even farther west, reverted to
# mountain time, which they had used before the advent of Nunavut's
# unified time zone in 1999.
# From Rives McDow (2001-01-20), quoting the Nunavut government:
# The preceding decision came into effect at midnight, Saturday Nov 4, 2000.
# From Paul Eggert (2000-12-04):
# Let's just keep track of the official times for now.
# From Rives McDow (2001-03-07):
# The premier of Nunavut has issued a ministerial statement advising
# that effective 2001-04-01, the territory of Nunavut will revert
# back to three time zones (mountain, central, and eastern). Of the
# cities in Nunavut, Coral Harbor is the only one that I know of that
# has said it will not observe dst, staying on EST year round. I'm
# checking for more info, and will get back to you if I come up with
# From Gwillim Law (2005-05-21):
# (from a 1998 Canadian Geographic article), the de facto and de jure time
# for Southampton Island (at the north end of Hudson Bay) is UTC-5 all year
# round. Using Google, it's easy to find other websites that confirm this.
# I wasn't able to find how far back this time regimen goes, but since it
# predates the creation of Nunavut, it probably goes back many years....
# The Inuktitut name of Coral Harbour is Sallit, but it's rarely used.
# From Paul Eggert (2005-07-26):
# For lack of better information, assume that Southampton Island observed
# daylight saving only during wartime.
# From Chris Walton (2007-03-01):
# ... the community of Resolute (located on Cornwallis Island in
# Nunavut) moved from Central Time to Eastern Time last November.
# Basically the community did not change its clocks at the end of
# From Chris Walton (2011-03-21):
# Back in 2007 I initiated the creation of a new "zone file" for Resolute
# Bay. Resolute Bay is a small community located about 900km north of
# the Arctic Circle. The zone file was required because Resolute Bay had
# decided to use UTC-5 instead of UTC-6 for the winter of 2006-2007.
# According to new information which I received last week, Resolute Bay
# went back to using UTC-6 in the winter of 2007-2008...
# On March 11/2007 most of Canada went onto daylight saving. On March
# 14/2007 I phoned the Resolute Bay hamlet office to do a "time check." I
# talked to somebody that was both knowledgeable and helpful. I was able
# to confirm that Resolute Bay was still operating on UTC-5. It was
# explained to me that Resolute Bay had been on the Eastern Time zone
# (EST) in the winter, and was now back on the Central Time zone (CDT).
#
i.e. the time zone had changed twice in the last year but the clocks
# had not moved. The residents had to know which time zone they were in
# so they could follow the correct TV schedule...
# On Nov 02/2008 most of Canada went onto standard time. On Nov 03/2008 I
# phoned the Resolute Bay hamlet office...[D]ue to the challenging nature
# of the phone call, I decided to seek out an alternate source of
# information. I found an e-mail address for somebody by the name of
# Stephanie Adams whose job was listed as "Inns North Support Officer for
# Arctic Co-operatives." I was under the impression that Stephanie lived
# and worked in Resolute Bay...
# On March 14/2011 I phoned the hamlet office again. I was told that
# Resolute Bay had been using Central Standard Time over the winter of
# 2010-2011 and that the clocks had therefore been moved one hour ahead
# on March 13/2011. The person I talked to was aware that Resolute Bay
# had previously experimented with Eastern Standard Time but he could not
# tell me when the practice had stopped.
# On March 17/2011 I searched the Web to find an e-mail address of
# somebody that might be able to tell me exactly when Resolute Bay went
# off Eastern Standard Time. I stumbled on the name "Aziz Kheraj." Aziz
# used to be the mayor of Resolute Bay and he apparently owns half the
# businesses including "South Camp Inn." This website has some info on
# I sent Aziz an e-mail asking when Resolute Bay had stopped using
# Aziz responded quickly with this: "hi, The time was not changed for the
# 1 year only, the following year, the community went back to the old way
# of "spring ahead-fall behind" currently we are zulu plus 5 hrs and in
# the winter Zulu plus 6 hrs"
# This of course conflicted with everything I had ascertained in November 2008.
# I sent Aziz a copy of my 2008 e-mail exchange with Stephanie. Aziz
# responded with this: "Hi, Stephanie lives in Winnipeg. I live here, You
# may want to check with the weather office in Resolute Bay or do a
# search on the weather through Env. Canada. web site"
# If I had realized the Stephanie did not live in Resolute Bay I would
# never have contacted her. I now believe that all the information I
# obtained in November 2008 should be ignored...
# I apologize for reporting incorrect information in 2008.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule NT_YK 1918 only - Apr 14 2:00 1:00 D
Rule NT_YK 1918 only - Oct 27 2:00 0 S
Rule NT_YK 1919 only - May 25 2:00 1:00 D
Rule NT_YK 1919 only - Nov 1 0:00 0 S
Rule NT_YK 1942 only - Feb 9 2:00 1:00 W # War
Rule NT_YK 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule NT_YK 1945 only - Sep 30 2:00 0 S
Rule NT_YK 1965 only - Apr lastSun 0:00 2:00 DD
Rule NT_YK 1965 only - Oct lastSun 2:00 0 S
Rule NT_YK 1980 1986 - Apr lastSun 2:00 1:00 D
Rule NT_YK 1980 2006 - Oct lastSun 2:00 0 S
Rule NT_YK 1987 2006 - Apr Sun>=1 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:00 NT_YK A%sT 1995 Apr Sun>=1 2:00
-5:00 Canada E%sT 1999 Oct 31 2:00
-6:00 Canada C%sT 2000 Oct 29 2:00
-5:00 NT_YK E%sT 1999 Oct 31 2:00
-6:00 Canada C%sT 2000 Oct 29 2:00
-6:00 NT_YK C%sT 2000 Oct 29 2:00
-5:00 - EST 2001 Apr 1 3:00
-6:00 Canada C%sT 2006 Oct 29 2:00
-5:00 - EST 2007 Mar 11 3:00
-6:00 NT_YK C%sT 2000 Oct 29 2:00
-5:00 - EST 2001 Apr 1 3:00
-7:00 NT_YK M%sT 1999 Oct 31 2:00
-6:00 Canada C%sT 2000 Oct 29 2:00
-5:00 - EST 2000 Nov 5 0:00
-6:00 - CST 2001 Apr 1 3:00
-8:00 NT_YK P%sT 1979 Apr lastSun 2:00
-9:00 NT_YK Y%sT 1966 Jul 1 2:00
-9:00 NT_YK Y%sT 1973 Oct 28 0:00
###############################################################################
# From Paul Eggert (2001-03-05):
# The Investigation and Analysis Service of the
# Mexican Library of Congress (MLoC) has published a
# history of Mexican local time (in Spanish)
# Here are the discrepancies between Shanks & Pottenger (S&P) and the MLoC.
# (In all cases we go with the MLoC.)
# S&P report that Baja was at -8:00 in 1922/1923.
# S&P say the 1930 transition in Baja was 1930-11-16.
# S&P report no DST during summer 1931.
# S&P report a transition at 1932-03-30 23:00, not 1932-04-01.
# From Gwillim Law (2001-02-20):
# There are some other discrepancies between the Decrees page and the
# tz database. I think they can best be explained by supposing that
# the researchers who prepared the Decrees page failed to find some of
# the relevant documents.
# From Alan Perry (1996-02-15):
# A guy from our Mexico subsidiary finally found the Presidential Decree
# outlining the timezone changes in Mexico.
# ------------- Begin Forwarded Message -------------
# I finally got my hands on the Official Presidential Decree that sets up the
# rules for the DST changes. The rules are:
# 1. The country is divided in 3 timezones:
# - Baja California Sur, Nayarit, Sinaloa and Sonora (the
Mexico/BajaSur TZ)
# 2. From the first Sunday in April at 2:00 AM to the last Sunday in October
# at 2:00 AM, the times in each zone are as follows:
# 3. The rest of the year, the times are as follows:
# The Decree was published in Mexico's Official Newspaper on January 4th.
# -------------- End Forwarded Message --------------
# From Paul Eggert (1996-06-12):
# For an English translation of the decree, see
# ``Diario Oficial: Time Zone Changeover'' (1996-01-04).
# From Rives McDow (1998-10-08):
# The State of Quintana Roo has reverted back to central STD and DST times
# (
i.e. UTC -0600 and -0500 as of 1998-08-02).
# From Rives McDow (2000-01-10):
# Effective April 4, 1999 at 2:00 AM local time, Sonora changed to the time
# zone 5 hours from the International Date Line, and will not observe daylight
# savings time so as to stay on the same time zone as the southern part of
# From Jesper Norgaard, translating
# In Oaxaca, the 55.000 teachers from the Section 22 of the National
# Syndicate of Education Workers, refuse to apply daylight saving each
# year, so that the more than 10,000 schools work at normal hour the
# From Gwillim Law (2001-01-19):
# January 17, 2000 - The Energy Secretary, Ernesto Martens, announced
# that Summer Time will be reduced from seven to five months, starting
# [translated], says "summer time will ... take effect on the first Sunday
# in May, and end on the last Sunday of September.
# From Arthur David Olson (2001-01-25):
# The 2001-01-24 traditional Washington Post contained the page one
# story "Timely Issue Divides Mexicans."...
# ... Mexico City Mayor Lopez Obrador "
...is threatening to keep
# Mexico City and its 20 million residents on a different time than
# the rest of the country..." In particular, Lopez Obrador would abolish
# observation of Daylight Saving Time.
# Official statute published by the Energy Department
# </a> (2001-02-01) shows Baja and Chihauhua as still using US DST rules,
# and Sonora with no DST. This was reported by Jesper Norgaard (2001-02-03).
# From Paul Eggert (2001-03-03):
# James F. Smith writes in today's LA Times
# * Sonora will continue to observe standard time.
# * Last week Mexico City's mayor Andres Manuel Lopez Obrador decreed that
# the Federal District will not adopt DST.
# * 4 of 16 district leaders announced they'll ignore the decree.
# * The decree does not affect federal-controlled facilities including
# the airport, banks, hospitals, and schools.
# For now we'll assume that the Federal District will bow to federal rules.
# From Jesper Norgaard (2001-04-01):
# I found some references to the Mexican application of daylight
# saving, which modifies what I had already sent you, stating earlier
# that a number of northern Mexican states would go on daylight
# saving. The modification reverts this to only cover Baja California
# (Norte), while all other states (except Sonora, who has no daylight
# saving all year) will follow the original decree of president
# Vicente Fox, starting daylight saving May 6, 2001 and ending
# From Reuters (2001-09-04):
# Mexico's Supreme Court on Tuesday declared that daylight savings was
# unconstitutional in Mexico City, creating the possibility the
# capital will be in a different time zone from the rest of the nation
# next year.... The Supreme Court's ruling takes effect at 2:00
#
a.m. (0800 GMT) on Sept. 30, when Mexico is scheduled to revert to
# standard time. "This is so residents of the Federal District are not
# subject to unexpected time changes," a statement from the court said.
# From Jesper Norgaard Welen (2002-03-12):
# ... consulting my local grocery store(!) and my coworkers, they all insisted
# that a new decision had been made to reinstate US style DST in Mexico....
# confirms this. Sonora as usual is the only state where DST is not applied.
# From Steffen Thorsen (2009-12-28):
# > Mexico's House of Representatives has approved a proposal for northern
# > Mexico's border cities to share the same daylight saving schedule as
# Now this has passed both the Congress and the Senate, so starting from
# 2010, some border regions will be the same:
# Could not find the new law text, but the proposed law text changes are here:
# There is also a list of the votes here:
# From Arthur David Olson (2010-01-20):
# En los municipios fronterizos de Tijuana y Mexicali en Baja California;
# Juárez y Ojinaga en Chihuahua; Acuña y Piedras Negras en Coahuila;
# Anáhuac en Nuevo León; y Nuevo Laredo, Reynosa y Matamoros en
# Tamaulipas, la aplicación de este horario estacional surtirá efecto
# desde las dos horas del segundo domingo de marzo y concluirá a las dos
# horas del primer domingo de noviembre.
# En los municipios fronterizos que se encuentren ubicados en la franja
# fronteriza norte en el territorio comprendido entre la línea
# internacional y la línea paralela ubicada a una distancia de veinte
# kilómetros, así como la Ciudad de Ensenada, Baja California, hacia el
# interior del país, la aplicación de este horario estacional surtirá
# efecto desde las dos horas del segundo domingo de marzo y concluirá a
# las dos horas del primer domingo de noviembre.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Mexico 1939 only - Feb 5 0:00 1:00 D
Rule Mexico 1939 only - Jun 25 0:00 0 S
Rule Mexico 1940 only - Dec 9 0:00 1:00 D
Rule Mexico 1941 only - Apr 1 0:00 0 S
Rule Mexico 1943 only - Dec 16 0:00 1:00 W # War
Rule Mexico 1944 only - May 1 0:00 0 S
Rule Mexico 1950 only - Feb 12 0:00 1:00 D
Rule Mexico 1950 only - Jul 30 0:00 0 S
Rule Mexico 1996 2000 - Apr Sun>=1 2:00 1:00 D
Rule Mexico 1996 2000 - Oct lastSun 2:00 0 S
Rule Mexico 2001 only - May Sun>=1 2:00 1:00 D
Rule Mexico 2001 only - Sep lastSun 2:00 0 S
Rule Mexico 2002 max - Apr Sun>=1 2:00 1:00 D
Rule Mexico 2002 max - Oct lastSun 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-5:00 Mexico E%sT 1998 Aug 2 2:00
# Coahuila, Durango, Nuevo Leon, Tamaulipas (near US border)
# Coahuila, Durango, Nuevo Leon, Tamaulipas (away from US border)
-7:00 - MST 1927 Jun 10 23:00
-7:00 - MST 1931 May 1 23:00
-6:00 Mexico C%sT 2001 Sep 30 02:00
# Chihuahua (near US border)
-7:00 - MST 1927 Jun 10 23:00
-7:00 - MST 1931 May 1 23:00
-6:00 - CST 1998 Apr Sun>=1 3:00
# Chihuahua (away from US border)
-7:00 - MST 1927 Jun 10 23:00
-7:00 - MST 1931 May 1 23:00
-6:00 - CST 1998 Apr Sun>=1 3:00
-7:00 - MST 1927 Jun 10 23:00
-7:00 - MST 1931 May 1 23:00
# From Alexander Krivenyshev (2010-04-21):
# According to news, Bahía de Banderas (Mexican state of Nayarit)
# changed time zone UTC-7 to new time zone UTC-6 on April 4, 2010 (to
# share the same time zone as nearby city Puerto Vallarta, Jalisco).
# Bahía de Banderas homologa su horario al del centro del
# país, a partir de este domingo
# Bahía de Banderas homologa su horario con el del Centro del
# Puerto Vallarta and Bahía de Banderas: One Time Zone
# "Mexico's Senate approved the amendments to the Mexican Schedule System that
# will allow Bahía de Banderas and Puerto Vallarta to share the same time
# Baja California Sur, Nayarit, Sinaloa
# From Arthur David Olson (2010-05-01):
# Use "Bahia_Banderas" to keep the name to fourteen characters.
-7:00 - MST 1927 Jun 10 23:00
-7:00 - MST 1931 May 1 23:00
-7:00 - MST 1927 Jun 10 23:00
-7:00 - MST 1931 May 1 23:00
-7:00 Mexico M%sT 2010 Apr 4 2:00
# Baja California (near US border)
-8:00 - PST 1927 Jun 10 23:00
-8:00 1:00 PDT 1931 Sep 30
-8:00 1:00 PWT 1945 Aug 14 23:00u
-8:00 1:00 PPT 1945 Nov 12 # Peace
-8:00 1:00 PDT 1949 Jan 14
-8:00 US P%sT 2002 Feb 20
# Baja California (away from US border)
-8:00 - PST 1927 Jun 10 23:00
-8:00 1:00 PDT 1931 Sep 30
-8:00 1:00 PWT 1945 Aug 14 23:00u
-8:00 1:00 PPT 1945 Nov 12 # Peace
-8:00 1:00 PDT 1949 Jan 14
-8:00 US P%sT 2002 Feb 20
# From Paul Eggert (2006-03-22):
# through 1995. This was as per Shanks (1999). But Shanks & Pottenger say
# Ensenada did not observe DST from 1948 through 1975. Guy Harris reports
# that the 1987 OAG says "Only Ensenada, Mexicale, San Felipe and
# Tijuana observe DST," which agrees with Shanks & Pottenger but implies that
# DST-observance was a town-by-town matter back then. This concerns
# data after 1970 so most likely there should be at least one Zone
# name or contents should be.
###############################################################################
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# From Sue Williams (2006-12-07):
# The Bahamas announced about a month ago that they plan to change their DST
# rules to sync with the
U.S. starting in 2007....
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Bahamas 1964 1975 - Oct lastSun 2:00 0 S
Rule Bahamas 1964 1975 - Apr lastSun 2:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Barb 1977 only - Jun 12 2:00 1:00 D
Rule Barb 1977 1978 - Oct Sun>=1 2:00 0 S
Rule Barb 1978 1980 - Apr Sun>=15 2:00 1:00 D
Rule Barb 1979 only - Sep 30 2:00 0 S
Rule Barb 1980 only - Sep 25 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-3:58:28 - BMT 1932 # Bridgetown Mean Time
# Whitman entirely disagrees with Shanks; go with Shanks & Pottenger.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Belize 1918 1942 - Oct Sun>=2 0:00 0:30 HD
Rule Belize 1919 1943 - Feb Sun>=9 0:00 0 S
Rule Belize 1973 only - Dec 5 0:00 1:00 D
Rule Belize 1974 only - Feb 9 0:00 0 S
Rule Belize 1982 only - Dec 18 0:00 1:00 D
Rule Belize 1983 only - Feb 12 0:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# From Dan Jones, reporting in The Royal Gazette (2006-06-26):
# Next year, however, clocks in the US will go forward on the second Sunday
# in March, until the first Sunday in November. And, after the Time Zone
# (Seasonal Variation) Bill 2006 was passed in the House of Assembly on
# Friday, the same thing will happen in Bermuda.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:00 - AST 1974 Apr 28 2:00
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-5:07:12 - KMT 1912 Feb # Kingston Mean Time
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule CR 1979 1980 - Feb lastSun 0:00 1:00 D
Rule CR 1979 1980 - Jun Sun>=1 0:00 0 S
Rule CR 1991 1992 - Jan Sat>=15 0:00 1:00 D
# IATA SSIM (1991-09) says the following was at 1:00;
# go with Shanks & Pottenger.
Rule CR 1991 only - Jul 1 0:00 0 S
Rule CR 1992 only - Mar 15 0:00 0 S
# There are too many San Joses elsewhere, so we'll use `Costa Rica'.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-5:36:20 - SJMT 1921 Jan 15 # San Jose Mean Time
# From Arthur David Olson (1999-03-29):
# The 1999-03-28 exhibition baseball game held in Havana, Cuba, between
# the Cuban National Team and the Baltimore Orioles was carried live on
# the Orioles Radio Network, including affiliate WTOP in Washington, DC.
# During the game, play-by-play announcer Jim Hunter noted that
# "We'll be losing two hours of
sleep...Cuba switched to Daylight Saving
# Time today." (The "two hour" remark referred to losing one hour of
# sleep on 1999-03-28--when the announcers were in Cuba as it switched
# to DST--and one more hour on 1999-04-04--when the announcers will have
# returned to Baltimore, which switches on that date.)
# From Evert van der Veer via Steffen Thorsen (2004-10-28):
# Cuba is not going back to standard time this year.
# From Paul Eggert (2006-03-22):
# says that it's due to a problem at the Antonio Guiteras
# thermoelectric plant, and says "This October there will be no return
# to normal hours (after daylight saving time)".
# For now, let's assume that it's a temporary measure.
# From Carlos A. Carnero Delgado (2005-11-12):
# This year (just like in 2004-2005) there's no change in time zone
# adjustment in Cuba. We will stay in daylight saving time:
# From Jesper Norgaard Welen (2006-10-21):
# An article in GRANMA INTERNACIONAL claims that Cuba will end
# the 3 years of permanent DST next weekend, see
# "On Saturday night, October 28 going into Sunday, October 29, at 01:00,
# watches should be set back one hour -- going back to 00:00 hours -- returning
# to the normal schedule....
# From Paul Eggert (2007-03-02):
# says Cuban clocks will advance at midnight on March 10.
# For lack of better information, assume Cuba will use US rules,
# except that it switches at midnight standard time as usual.
# From Steffen Thorsen (2007-10-25):
# Carlos Alberto Fonseca Arauz informed me that Cuba will end DST one week
# earlier - on the last Sunday of October, just like in 2006.
# He supplied these references:
# From Alex Kryvenishev (2007-10-25):
# Here is also article from Granma (Cuba):
# [Regira] el Horario Normal desde el [proximo] domingo 28 de octubre
# From Arthur David Olson (2008-03-09):
# I'm in Maryland which is now observing United States Eastern Daylight
# Time. At 9:44 local time I used RealPlayer to listen to
# </a>, a Cuban information station, and heard
# the time announced as "ocho cuarenta y cuatro" ("eight forty-four"),
# indicating that Cuba is still on standard time.
# From Steffen Thorsen (2008-03-12):
# It seems that Cuba will start DST on Sunday, 2007-03-16...
# It was announced yesterday, according to this source (in Spanish):
# Some more background information is posted here:
# The article also says that Cuba has been observing DST since 1963,
# while Shanks (and tzdata) has 1965 as the first date (except in the
# 1940's). Many other web pages in Cuba also claim that it has been
# observed since 1963, but with the exception of 1970 - an exception
# which is not present in
tzdata/Shanks. So there is a chance we need to
# change some historic records as well.
# From Jesper Norgaard Welen (2008-03-13):
# The Cuban time change has just been confirmed on the most authoritative
# web site, the Granma. Please check out
# Basically as expected after Steffen Thorsens information, the change
# will take place midnight between Saturday and Sunday.
# From Arthur David Olson (2008-03-12):
# Assume Sun>=15 (third Sunday) going forward.
# From Alexander Krivenyshev (2009-03-04)
# According to the Radio Reloj - Cuba will start Daylight Saving Time on
# midnight between Saturday, March 07, 2009 and Sunday, March 08, 2009-
# not on midnight March 14 / March 15 as previously thought.
# From Arthur David Olson (2009-03-09)
# I listened over the Internet to
# this morning; when it was 10:05 a. m. here in Bethesda, Maryland the
# the time was announced as "diez cinco"--the same time as here, indicating
# that has indeed switched to DST. Assume second Sunday from 2009 forward.
# From Steffen Thorsen (2011-03-08):
# Granma announced that Cuba is going to start DST on 2011-03-20 00:00:00
# this year. Nothing about the end date known so far (if that has
# From Steffen Thorsen (2011-10-30)
# Cuba will end DST two weeks later this year. Instead of going back
# tonight, it has been delayed to 2011-11-13 at 01:00.
# From Steffen Thorsen (2012-03-01)
# According to Radio Reloj, Cuba will start DST on Midnight between March
# Radio Reloj has the following info (Spanish):
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Cuba 1928 only - Jun 10 0:00 1:00 D
Rule Cuba 1928 only - Oct 10 0:00 0 S
Rule Cuba 1940 1942 - Jun Sun>=1 0:00 1:00 D
Rule Cuba 1940 1942 - Sep Sun>=1 0:00 0 S
Rule Cuba 1945 1946 - Jun Sun>=1 0:00 1:00 D
Rule Cuba 1945 1946 - Sep Sun>=1 0:00 0 S
Rule Cuba 1965 only - Jun 1 0:00 1:00 D
Rule Cuba 1965 only - Sep 30 0:00 0 S
Rule Cuba 1966 only - May 29 0:00 1:00 D
Rule Cuba 1966 only - Oct 2 0:00 0 S
Rule Cuba 1967 only - Apr 8 0:00 1:00 D
Rule Cuba 1967 1968 - Sep Sun>=8 0:00 0 S
Rule Cuba 1968 only - Apr 14 0:00 1:00 D
Rule Cuba 1969 1977 - Apr lastSun 0:00 1:00 D
Rule Cuba 1969 1971 - Oct lastSun 0:00 0 S
Rule Cuba 1972 1974 - Oct 8 0:00 0 S
Rule Cuba 1975 1977 - Oct lastSun 0:00 0 S
Rule Cuba 1978 only - May 7 0:00 1:00 D
Rule Cuba 1978 1990 - Oct Sun>=8 0:00 0 S
Rule Cuba 1979 1980 - Mar Sun>=15 0:00 1:00 D
Rule Cuba 1981 1985 - May Sun>=5 0:00 1:00 D
Rule Cuba 1986 1989 - Mar Sun>=14 0:00 1:00 D
Rule Cuba 1990 1997 - Apr Sun>=1 0:00 1:00 D
Rule Cuba 1991 1995 - Oct Sun>=8 0:00s 0 S
Rule Cuba 1996 only - Oct 6 0:00s 0 S
Rule Cuba 1997 only - Oct 12 0:00s 0 S
Rule Cuba 1998 1999 - Mar lastSun 0:00s 1:00 D
Rule Cuba 1998 2003 - Oct lastSun 0:00s 0 S
Rule Cuba 2000 2004 - Apr Sun>=1 0:00s 1:00 D
Rule Cuba 2006 2010 - Oct lastSun 0:00s 0 S
Rule Cuba 2007 only - Mar Sun>=8 0:00s 1:00 D
Rule Cuba 2008 only - Mar Sun>=15 0:00s 1:00 D
Rule Cuba 2009 2010 - Mar Sun>=8 0:00s 1:00 D
Rule Cuba 2011 only - Mar Sun>=15 0:00s 1:00 D
Rule Cuba 2011 only - Nov 13 0:00s 0 S
Rule Cuba 2012 only - Apr 1 0:00s 1:00 D
Rule Cuba 2012 max - Oct lastSun 0:00s 0 S
Rule Cuba 2013 max - Mar Sun>=8 0:00s 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-5:29:36 - HMT 1925 Jul 19 12:00 # Havana MT
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# From Steffen Thorsen (2000-10-30):
# Enrique Morales reported to me that the Dominican Republic has changed the
# time zone to Eastern Standard Time as of Sunday 29 at 2 am....
# From Paul Eggert (2000-12-04):
# That URL (2000-10-26, in Spanish) says they planned to use US-style DST.
# From Rives McDow (2000-12-01):
# Dominican Republic changed its mind and presidential decree on Tuesday,
# November 28, 2000, with a new decree. On Sunday, December 3 at 1:00 AM the
# Dominican Republic will be reverting to 8 hours from the International Date
# Line, and will not be using DST in the foreseeable future. The reason they
# decided to use DST was to be in synch with Puerto Rico, who was also going
# to implement DST. When Puerto Rico didn't implement DST, the president
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule DR 1966 only - Oct 30 0:00 1:00 D
Rule DR 1967 only - Feb 28 0:00 0 S
Rule DR 1969 1973 - Oct lastSun 0:00 0:30 HD
Rule DR 1970 only - Feb 21 0:00 0 S
Rule DR 1971 only - Jan 20 0:00 0 S
Rule DR 1972 1974 - Jan 21 0:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:40 - SDMT 1933 Apr 1 12:00 # S. Dom. MT
-5:00 DR E%sT 1974 Oct 27
-4:00 - AST 2000 Oct 29 02:00
-5:00 US E%sT 2000 Dec 3 01:00
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Salv 1987 1988 - May Sun>=1 0:00 1:00 D
Rule Salv 1987 1988 - Sep lastSun 0:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# St Martin (French part)
# From Gwillim Law (2006-04-22), after a heads-up from Oscar van Vlijmen:
# says in an article dated 2006-04-19 that the Guatemalan government had
# decided on that date to advance official time by 60 minutes, to lessen the
# impact of the elevated cost of oil.... Daylight saving time will last from
# 2006-04-29 24:00 (Guatemalan standard time) to 2006-09-30 (time unspecified).
# From Paul Eggert (2006-06-22):
# The Ministry of Energy and Mines, press release CP-15/2006
# (2006-04-19), says DST ends at 24:00. See
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Guat 1973 only - Nov 25 0:00 1:00 D
Rule Guat 1974 only - Feb 24 0:00 0 S
Rule Guat 1983 only - May 21 0:00 1:00 D
Rule Guat 1983 only - Sep 22 0:00 0 S
Rule Guat 1991 only - Mar 23 0:00 1:00 D
Rule Guat 1991 only - Sep 7 0:00 0 S
Rule Guat 2006 only - Apr 30 0:00 1:00 D
Rule Guat 2006 only - Oct 1 0:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# From Gwillim Law (2005-04-15):
# Risto O. Nykanen wrote me that Haiti is now on DST.
# I searched for confirmation, and I found a
# on the Web page of the Haitian Consulate in Chicago (2005-03-31),
# </a>. Translated from French, it says:
# "The Prime Minister's Communication Office notifies the public in general
# and the press in particular that, following a decision of the Interior
# Ministry and the Territorial Collectivities [I suppose that means the
# provinces], Haiti will move to Eastern Daylight Time in the night from next
# Saturday the 2nd to Sunday the 3rd.
# "Consequently, the Prime Minister's Communication Office wishes to inform
# the population that the country's clocks will be set forward one hour
# starting at midnight. This provision will hold until the last Saturday in
# "Port-au-Prince, March 31, 2005"
# From Steffen Thorsen (2006-04-04):
# I have been informed by users that Haiti observes DST this year like
# last year, so the current "only" rule for 2005 might be changed to a
# "max" rule or to last until 2006. (Who knows if they will observe DST
# next year or if they will extend their DST like
US/Canada next year).
# I have found this article about it (in French):
# The reason seems to be an energy crisis.
# From Stephen Colebourne (2007-02-22):
# Some IATA info: Haiti won't be having DST in 2007.
# From Steffen Thorsen (2012-03-11):
# According to several news sources, Haiti will observe DST this year,
# apparently using the same start and end date as
USA/Canada.
# So this means they have already changed their time.
# From Arthur David Olson (2012-03-11):
# 3:00
a.m. rather than the traditional Haitian jump at midnight.
# Assume a US-style fall back as well XXX.
# Do not yet assume that the change carries forward past 2012 XXX.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Haiti 1983 only - May 8 0:00 1:00 D
Rule Haiti 1984 1987 - Apr lastSun 0:00 1:00 D
Rule Haiti 1983 1987 - Oct lastSun 0:00 0 S
# Shanks & Pottenger say AT is 2:00, but IATA SSIM (1991/1997) says 1:00s.
Rule Haiti 1988 1997 - Apr Sun>=1 1:00s 1:00 D
Rule Haiti 1988 1997 - Oct lastSun 1:00s 0 S
Rule Haiti 2005 2006 - Apr Sun>=1 0:00 1:00 D
Rule Haiti 2005 2006 - Oct lastSun 0:00 0 S
Rule Haiti 2012 only - Mar Sun>=8 2:00 1:00 D
Rule Haiti 2012 only - Nov Sun>=1 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:49 - PPMT 1917 Jan 24 12:00 # P-a-P MT
# Shanks & Pottenger say 1921 Jan 1; go with Whitman's more precise Apr 1.
# From Paul Eggert (2006-05-05):
# saying Honduras will start using DST midnight Saturday, effective 4
# months until September. La Tribuna reported today
# of Honduras, refused to back down on this.
# From Jesper Norgaard Welen (2006-08-08):
# It seems that Honduras has returned from DST to standard time this Monday at
# 00:00 hours (prolonging Sunday to 25 hours duration).
# From Paul Eggert (2006-08-08):
# Also see Diario El Heraldo, The country returns to standard time (2006-08-08)
# It mentions executive decree 18-2006.
# From Steffen Thorsen (2006-08-17):
# Honduras will observe DST from 2007 to 2009, exact dates are not
# published, I have located this authoritative source:
# From Steffen Thorsen (2007-03-30):
# So it seems that Honduras will not enter DST this year....
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Hond 1987 1988 - May Sun>=1 0:00 1:00 D
Rule Hond 1987 1988 - Sep lastSun 0:00 0 S
Rule Hond 2006 only - May Sun>=1 0:00 1:00 D
Rule Hond 2006 only - Aug Mon>=1 0:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# Great Swan I ceded by US to Honduras in 1972
# From Bob Devine (1988-01-28):
# From U. S. Naval Observatory (1989-01-19):
# From Shanks & Pottenger:
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-5:07:12 - KMT 1912 Feb # Kingston Mean Time
-5:00 - EST 1974 Apr 28 2:00
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:04:20 - FFMT 1911 May # Fort-de-France MT
-4:00 1:00 ADT 1980 Sep 28
# From Paul Eggert (2006-03-22):
# In 1995 volcanic eruptions forced evacuation of Plymouth, the capital.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# This uses Shanks & Pottenger for times before 2005.
# From Steffen Thorsen (2005-04-12):
# I've got reports from 8 different people that Nicaragua just started
# DST on Sunday 2005-04-10, in order to save energy because of
# expensive petroleum. The exact end date for DST is not yet
# announced, only "September" but some sites also say "mid-September".
# Some background information is available on the President's official site:
# The Decree, no 23-2005 is available here:
# From Paul Eggert (2005-05-01):
# The decree doesn't say anything about daylight saving, but for now let's
# assume that it is daylight saving....
# From Gwillim Law (2005-04-21):
# The Associated Press story on the time change, which can be found at
# and elsewhere, says (fifth paragraph, translated from Spanish): "The last
# time that a change of clocks was applied to save energy was in the year 2000
# during the Arnoldo Aleman administration."...
# The northamerica file says that Nicaragua has been on UTC-6 continuously
# since December 1998. I wasn't able to find any details of Nicaraguan time
# changes in 2000. Perhaps a note could be added to the northamerica file, to
# the effect that we have indirect evidence that DST was observed in 2000.
# From Jesper Norgaard Welen (2005-11-02):
# Nicaragua left DST the 2005-10-02 at 00:00 (local time).
# From Jesper Norgaard Welen (2006-05-05):
# (my informal translation)
# By order of the president of the republic, Enrique Bolanos, Nicaragua
# advanced by sixty minutes their official time, yesterday at 2 in the
# morning, and will stay that way until
30.th. of september.
# From Jesper Norgaard Welen (2006-09-30):
# My informal translation runs:
# The natural sun time is restored in all the national territory, in that the
# time is returned one hour at 01:00 am of October 1 of 2006.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Nic 1979 1980 - Mar Sun>=16 0:00 1:00 D
Rule Nic 1979 1980 - Jun Mon>=23 0:00 0 S
Rule Nic 2005 only - Apr 10 0:00 1:00 D
Rule Nic 2005 only - Oct Sun>=1 0:00 0 S
Rule Nic 2006 only - Apr 30 2:00 1:00 D
Rule Nic 2006 only - Oct Sun>=1 1:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-5:45:12 - MMT 1934 Jun 23 # Managua Mean Time?
-6:00 Nic C%sT 1992 Jan 1 4:00
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-5:19:36 - CMT 1908 Apr 22 # Colon Mean Time
# There are too many San Juans elsewhere, so we'll use `Puerto_Rico'.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:04:00 - CMT 1912 # Castries Mean Time
# There are too many St Pierres elsewhere, so we'll use `Miquelon'.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-3:00 - PMST 1987 # Pierre & Miquelon Time
# St Vincent and the Grenadines
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:04:56 - KMT 1912 # Kingstown Mean Time
# daylight saving dates for time changes have been adjusted to match
# the recent
U.S. change of dates.
# From Brian Inglis (2007-04-28):
# there is an entry for Nov 4 "Daylight Savings Time Ends 2007" and three
# rows before that there is an out of date entry for Oct:
# "Eastern Standard Times Begins 2007
# Clocks are set back one hour at 2:00
a.m. local Daylight Saving Time"
# indicating that the normal ET rules are followed.
# From Paul Eggert (2006-05-01):
# Shanks & Pottenger say they use US DST rules, but IATA SSIM (1991/1998)
# says they switch at midnight. Go with Shanks & Pottenger.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule TC 1979 1986 - Apr lastSun 2:00 1:00 D
Rule TC 1979 2006 - Oct lastSun 2:00 0 S
Rule TC 1987 2006 - Apr Sun>=1 2:00 1:00 D
Rule TC 2007 max - Mar Sun>=8 2:00 1:00 D
Rule TC 2007 max - Nov Sun>=1 2:00 0 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-5:07:12 - KMT 1912 Feb # Kingston Mean Time
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# Zone NAME GMTOFF RULES FORMAT [UNTIL]