Rule Arg 1932 1939 - Nov 1 0:00 1:00 S
Rule Arg 1940 only - Jul 1 0:00 1:00 S
Rule Arg 1941 only - Jun 15 0:00 0 -
Rule Arg 1941 only - Oct 15 0:00 1:00 S
Rule Arg 1943 only - Aug 1 0:00 0 -
Rule Arg 1943 only - Oct 15 0:00 1:00 S
Rule Arg 1946 only - Mar 1 0:00 0 -
Rule Arg 1946 only - Oct 1 0:00 1:00 S
Rule Arg 1963 only - Oct 1 0:00 0 -
Rule Arg 1963 only - Dec 15 0:00 1:00 S
Rule Arg 1964 1966 - Mar 1 0:00 0 -
Rule Arg 1964 1966 - Oct 15 0:00 1:00 S
Rule Arg 1967 only - Apr 2 0:00 0 -
Rule Arg 1967 1968 - Oct Sun>=1 0:00 1:00 S
Rule Arg 1968 1969 - Apr Sun>=1 0:00 0 -
Rule Arg 1974 only - Jan 23 0:00 1:00 S
Rule Arg 1974 only - May 1 0:00 0 -
Rule Arg 1988 only - Dec 1 0:00 1:00 S
# From Hernan G. Otero (1995-06-26):
# These corrections were contributed by InterSoft Argentina
S.A.,
# obtaining the data from the:
# Talleres de Hidrografia Naval Argentina
# (Argentine Naval Hydrography Institute)
Rule Arg 1989 1993 - Mar Sun>=1 0:00 0 -
Rule Arg 1989 1992 - Oct Sun>=15 0:00 1:00 S
# From Hernan G. Otero (1995-06-26):
# From this moment on, the law that mandated the daylight saving
# time corrections was derogated and no more modifications
# to the time zones (for daylight saving) are now made.
# From Rives McDow (2000-01-10):
# On October 3, 1999, 0:00 local, Argentina implemented daylight savings time,
# which did not result in the switch of a time zone, as they stayed 9 hours
# from the International Date Line.
Rule Arg 1999 only - Oct Sun>=1 0:00 1:00 S
# From Paul Eggert (2007-12-28):
# DST was set to expire on March 5, not March 3, but since it was converted
# to standard time on March 3 it's more convenient for us to pretend that
Rule Arg 2000 only - Mar 3 0:00 0 -
# From Peter Gradelski via Steffen Thorsen (2000-03-01):
# We just checked with our Sao Paulo office and they say the government of
# Argentina decided not to become one of the countries that go on or off DST.
# So Buenos Aires should be -3 hours from GMT at all times.
# From Fabian L. Arce Jofre (2000-04-04):
# The law that claimed DST for Argentina was derogated by President Fernando
# de la Rua on March 2, 2000, because it would make people spend more energy
# in the winter time, rather than less. The change took effect on March 3.
# From Mariano Absatz (2001-06-06):
# one of the major newspapers here in Argentina said that the 1999
# Timezone Law (which never was effectively applied) will (would?) be
# in effect.... The article is at
# ... The Law itself is "Ley No 25155", sanctioned on 1999-08-25, enacted
# 1999-09-17, and published 1999-09-21. The official publication is at:
# Regretfully, you have to subscribe (and pay) for the on-line version....
# the timezone for Argentina will not change next Sunday.
# Apparently it will do so on Sunday 24th....
# Last Friday (yes, the last working day before the date of the change), the
# Senate annulled the 1999 law that introduced the changes later postponed.
# It remains the vote of the Deputies..., but it will be the same....
# This kind of things had always been done this way in Argentina.
# We are still -03:00 all year round in all of the country.
# From Steffen Thorsen (2007-12-21):
# A user (Leonardo Chaim) reported that Argentina will adopt DST....
# all of the country (all Zone-entries) are affected. News reports like
# that Argentina will use DST next year as well, from October to
# March, although exact rules are not given.
# From Jesper Norgaard Welen (2007-12-26)
# The last hurdle of Argentina DST is over, the proposal was approved in
# the lower chamber too (Deputados) with a vote 192 for and 2 against.
# By the way thanks to Mariano Absatz and Daniel Mario Vega for the link to
# the original scanned proposal, where the dates and the zero hours are
# From Paul Eggert (2007-12-22):
# For dates after mid-2008, the following rules are my guesses and
# are quite possibly wrong, but are more likely than no DST at all.
# From Alexander Krivenyshev (2008-09-05):
# As per message from Carlos Alberto Fonseca Arauz (Nicaragua),
# Argentina will start DST on Sunday October 19, 2008.
# From Rodrigo Severo (2008-10-06):
# Here is some info available at a Gentoo bug related to TZ on Argentina's DST:
# ------- Comment #1 from [jmdocile] 2008-10-06 16:28 0000 -------
# Hi, there is a problem with timezone-data-2008e and maybe with
# Argentinian law [Number] 25.155 is no longer valid.
# The new one is law [Number] 26.350
# So there is no summer time in Argentina for now.
# From Mariano Absatz (2008-10-20):
# Decree 1693/2008 applies Law 26.350 for the summer 2008/2009 establishing DST in Argentina
# From 2008-10-19 until 2009-03-15
# Decree 1705/2008 excepting 12 Provinces from applying DST in the summer 2008/2009:
# Catamarca, La Rioja, Mendoza, Salta, San Juan, San Luis, La Pampa, Neuquen, Rio Negro, Chubut, Santa Cruz
# Press release 235 dated Saturday October 18th, from the Government of the Province of Jujuy saying
# it will not apply DST either (even when it was not included in Decree 1705/2008)
# From fullinet (2009-10-18):
# (an official
.gob.ar) under title: "Sin Cambio de Hora" (english: "No hour change")
# "Por el momento, el Gobierno Nacional resolvio no modificar la hora
# oficial, decision que estaba en estudio para su implementacion el
# domingo 18 de octubre. Desde el Ministerio de Planificacion se anuncio
# que la Argentina hoy, en estas condiciones meteorologicas, no necesita
# la modificacion del huso horario, ya que 2009 nos encuentra con
# crecimiento en la produccion y distribucion energetica."
Rule Arg 2007 only - Dec 30 0:00 1:00 S
Rule Arg 2008 2009 - Mar Sun>=15 0:00 0 -
Rule Arg 2008 only - Oct Sun>=15 0:00 1:00 S
# From Mariano Absatz (2004-05-21):
# Today it was officially published that the Province of Mendoza is changing
# its timezone this winter... starting tomorrow night....
# From Paul Eggert (2004-05-24):
# It's Law No. 7,210. This change is due to a public power emergency, so for
# now we'll assume it's for this year only.
# From Paul Eggert (2006-03-22):
# Hora de verano para la Republica Argentina (2003-06-08)
# </a> says that standard time in Argentina from 1894-10-31
# to 1920-05-01 was -4:16:48.25. Go with this more-precise value
# over Shanks & Pottenger.
# From Mariano Absatz (2004-06-05):
# These media articles from a major newspaper mostly cover the current state:
# The following eight (8) provinces pulled clocks back to UTC-04:00 at
# midnight Monday May 31st. (that is, the night between 05/31 and 06/01).
# Apparently, all nine provinces would go back to UTC-03:00 at the same
# Catamarca, Chubut, La Rioja, San Juan, San Luis, Santa Cruz,
# Tierra del Fuego, Tucuman.
# From Mariano Absatz (2004-06-14):
# ... this weekend, the Province of Tucuman decided it'd go back to UTC-03:00
# yesterday midnight (that is, at 24:00 Saturday 12th), since the people's
# annoyance with the change is much higher than the power savings obtained....
# From Gwillim Law (2004-06-14):
# "The time change in Tierra del Fuego was a conflicted decision from
# the start. The government had decreed that the measure would take
# effect on June 1, but a normative error forced the new time to begin
# three days earlier, from a Saturday to a Sunday....
# Our understanding was that the change was originally scheduled to take place
# on June 1 at 00:00 in Chubut, Santa Cruz, Tierra del Fuego (and some other
# provinces). Sunday was May 30, only two days earlier. So the article
# contains a contradiction. I would give more credence to the
Saturday/Sunday# date than the "three days earlier" phrase, and conclude that Tierra del
# Fuego set its clocks back at 2004-05-30 00:00.
# From Steffen Thorsen (2004-10-05):
# The previous law 7210 which changed the province of Mendoza's time zone
# back in May have been modified slightly in a new law 7277, which set the
# new end date to 2004-09-26 (original date was 2004-10-17).
# From Mariano Absatz (2004-10-05):
# San Juan changed from UTC-03:00 to UTC-04:00 at midnight between
# Sunday, May 30th and Monday, May 31st. It changed back to UTC-03:00
# at midnight between Saturday, July 24th and Sunday, July 25th....
# From Alex Krivenyshev (2008-01-17):
# Here are articles that Argentina Province San Luis is planning to end DST
# as earlier as upcoming Monday January 21, 2008 or February 2008:
# Provincia argentina retrasa reloj y marca diferencia con resto del pais
# (Argentine Province delayed clock and mark difference with the rest of the
# Es inminente que en San Luis atrasen una hora los relojes
# (It is imminent in San Luis clocks one hour delay)
# From Jesper Norgaard Welen (2008-01-18):
# The page of the San Luis provincial government
# confirms what Alex Krivenyshev has earlier sent to the tz
# emailing list about that San Luis plans to return to standard
# time much earlier than the rest of the country. It also
# confirms that upon request the provinces San Juan and Mendoza
# refused to follow San Luis in this change.
# The change is supposed to take place Monday the
21.st at 0:00
# hours. As far as I understand it if this goes ahead, we need
# a new timezone for San Luis (although there are also documented
# independent changes in the southamerica file of San Luis in
# 1990 and 1991 which has not been confirmed).
# From Jesper Norgaard Welen (2008-01-25):
# Unfortunately the below page has become defunct, about the San Luis
# time change. Perhaps because it now is part of a group of pages "Most
# important pages of 2008."
# instead it seems. Or use "Buscador" from the main page of the San Luis
# government, and fill in "huso" and click OK, and you will get 3 pages
# from which the first one is identical to the above.
# From Mariano Absatz (2008-01-28):
# I can confirm that the Province of San Luis (and so far only that
# province) decided to go back to UTC-3 effective midnight Jan 20th 2008
# (that is, Monday 21st at 0:00 is the time the clocks were delayed back
# 1 hour), and they intend to keep UTC-3 as their timezone all year round
# (that is, unless they change their mind any minute now).
# So we'll have to add yet another city to 'southamerica' (I think San
# Luis city is the mos populated city in the Province, so it'd be
# history of particular changes goes along with Mendoza or San Juan :-(
# (I only remember not being able to collect hard facts about San Luis
# back in 2004, when these provinces changed to UTC-4 for a few days, I
# mailed them personally and never got an answer).
# From Paul Eggert (2008-06-30):
# Unless otherwise specified, data are from Shanks & Pottenger through 1992,
# from the IATA otherwise. As noted below, Shanks & Pottenger say that
# From Mariano Absatz (2009-03-13):
# Yesterday (with our usual 2-day notice) the Province of San Luis
# decided that next Sunday instead of "staying" @utc-03:00 they will go
# to utc-04:00 until the second Saturday in October...
# The press release is at
# (I couldn't find the decree, but
# is the official page for the Province Government).
# There's also a note in only one of the major national papers ...
# The press release says [quick and dirty translation]:
# ... announced that next Sunday, at 00:00, Puntanos (the San Luis
# inhabitants) will have to turn back one hour their clocks
# Since then, San Luis will establish its own Province timezone. Thus,
# during 2009, this timezone change will run from 00:00 the third Sunday
# in March until 24:00 of the second Saturday in October.
# From Mariano Absatz (2009-10-16):
#
...the Province of San Luis is a case in itself.
# is ambiguous because establishes a calendar from the 2nd Sunday in
# October at 0:00 thru the 2nd Saturday in March at 24:00 and the
# complement of that starting on the 2nd Sunday of March at 0:00 and
# ending on the 2nd Saturday of March at 24:00.
# This clearly breaks every time the 1st of March or October is a Sunday.
# IMHO, the "spirit of the Law" is to make the changes at 0:00 on the 2nd
# Sunday of October and March.
# The problem is that the changes in the rest of the Provinces that did
# change in 2007/2008, were made according to the Federal Law and Decrees
# that did so on the 3rd Sunday of October and March.
# In fact, San Luis actually switched from UTC-4 to UTC-3 last Sunday
# (October 11th) at 0:00.
# So I guess a new set of rules, besides "Arg", must be made and the last
# I'm enclosing a patch that does what I say... regretfully, the San Luis
# timezone must be called "
WART/WARST" even when most of the time (like,
# right now) WARST == ART... that is, since last Sunday, all the country
# is using UTC-3, but in my patch, San Luis calls it "WARST" and the rest
# of the country calls it "ART".
# From Alexander Krivenyshev (2010-04-09):
# According to news reports from El Diario de la Republica Province San
# Luis, Argentina (standard time UTC-04) will keep Daylight Saving Time
# after April 11, 2010--will continue to have same time as rest of
# Argentina (UTC-3) (no DST).
# Confirmaron la prórroga del huso horario de verano (Spanish)
# or (some English translation):
# From Mariano Absatz (2010-04-12):
# UTC-03:00 "summer time", we should't just let San Luis go back to "Arg"
#
rules...San Luis is still using "Western ARgentina Time" and it got
# stuck on Summer daylight savings time even though the summer is over.
# From Paul Eggert (2013-02-21):
# Milne says Cordoba time was -4:16:48.2. Round to the nearest second.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# Buenos Aires (BA), Capital Federal (CF),
-4:16:48 - CMT 1920 May # Cordoba Mean Time
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
# Cordoba (CB), Santa Fe (SF), Entre Rios (ER), Corrientes (CN), Misiones (MN),
# Chaco (CC), Formosa (FM), Santiago del Estero (SE)
# Shanks & Pottenger also make the following claims, which we haven't verified:
# - Formosa switched to -3:00 on 1991-01-07.
# - Misiones switched to -3:00 on 1990-12-29.
# - Chaco switched to -3:00 on 1991-01-04.
# - Santiago del Estero switched to -4:00 on 1991-04-01,
# then to -3:00 on 1991-04-26.
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Mar 3
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
# Salta (SA), La Pampa (LP), Neuquen (NQ), Rio Negro (RN)
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Mar 3
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 Arg AR%sT 2008 Oct 18
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Mar 3
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Mar 1
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 Arg AR%sT 2008 Oct 18
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Mar 1
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 Arg AR%sT 2008 Oct 18
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1990 Mar 4
-4:00 1:00 WARST 1991 Mar 17
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 Arg AR%sT 2008 Oct 18
# Catamarca (CT), Chubut (CH)
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Mar 3
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 Arg AR%sT 2008 Oct 18
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1990 Mar 4
-4:00 1:00 WARST 1991 Mar 1
-4:00 1:00 WARST 1992 Mar 1
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 Arg AR%sT 2008 Oct 18
Rule SanLuis 2008 2009 - Mar Sun>=8 0:00 0 -
Rule SanLuis 2007 2009 - Oct Sun>=8 0:00 1:00 S
-4:00 Arg AR%sT 1969 Oct 5
-3:00 1:00 ARST 1990 Mar 14
-4:00 1:00 WARST 1991 Mar 1
-4:00 1:00 WARST 2000 Mar 3
-3:00 Arg AR%sT 2008 Jan 21
-4:16:48 - CMT 1920 May # Cordoba Mean Time
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 Arg AR%sT 2008 Oct 18
# Tierra del Fuego, Antartida e Islas del Atlantico Sur (TF)
-4:16:48 - CMT 1920 May # Cordoba Mean Time
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 Arg AR%sT 2008 Oct 18
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:30 - ANT 1965 # Netherlands Antilles Time
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:32:36 - CMT 1931 Oct 15 # Calamarca MT
-4:32:36 1:00 BOST 1932 Mar 21 # Bolivia ST
-4:00 - BOT # Bolivia Time
# From Paul Eggert (1993-11-18):
# The mayor of Rio recently attempted to change the time zone rules
# just in his city, in order to leave more summer time for the tourist trade.
# The rule change lasted only part of the day;
# the federal government refused to follow the city's rules, and business
# was in a chaos, so the mayor backed down that afternoon.
# From IATA SSIM (1996-02):
# _Only_ the following states in BR1 observe DST: Rio Grande do Sul (RS),
# Santa Catarina (SC), Parana (PR), Sao Paulo (SP), Rio de Janeiro (RJ),
# Espirito Santo (ES), Minas Gerais (MG), Bahia (BA), Goias (GO),
# Distrito Federal (DF), Tocantins (TO), Sergipe [SE] and Alagoas [AL].
# [The last three states are new to this issue of the IATA SSIM.]
# From Gwillim Law (1996-10-07):
# Geography, history (Tocantins was part of Goias until 1989), and other
# sources of time zone information lead me to believe that AL, SE, and TO were
# always in BR1, and so the only change was whether or not they observed DST....
# The earliest issue of the SSIM I have is 2/91. Each issue from then until
# 9/95 says that DST is observed only in the ten states I quoted from 9/95,
# along with Mato Grosso (MT) and Mato Grosso do Sul (MS), which are in BR2
# (UTC-4).... The other two time zones given for Brazil are BR3, which is
# UTC-5, no DST, and applies only in the state of Acre (AC); and BR4, which is
# UTC-2, and applies to Fernando de Noronha (formerly FN, but I believe it's
# become part of the state of Pernambuco). The boundary between BR1 and BR2
# has never been clearly stated. They've simply been called East and West.
# However, some conclusions can be drawn from another IATA manual: the Airline
# Coding Directory, which lists close to 400 airports in Brazil. For each
# airport it gives a time zone which is coded to the SSIM. From that
# information, I'm led to conclude that the states of Amapa (AP), Ceara (CE),
# Maranhao (MA), Paraiba (PR), Pernambuco (PE), Piaui (PI), and Rio Grande do
# Norte (RN), and the eastern part of Para (PA) are all in BR1 without DST.
# From Marcos Tadeu (1998-09-27):
# Brazilian official page
# From Jesper Norgaard (2000-11-03):
# [For an official list of which regions in Brazil use which time zones, see:]
# From Celso Doria via David Madeo (2002-10-09):
# The reason for the delay this year has to do with elections in Brazil.
# Unlike in the United States, elections in Brazil are 100% computerized and
# the results are known almost immediately. Yesterday, it was the first
# round of the elections when 115 million Brazilians voted for President,
# Governor, Senators, Federal Deputies, and State Deputies. Nobody is
# counting (or re-counting) votes anymore and we know there will be a second
# round for the Presidency and also for some Governors. The 2nd round will
# take place on October 27th.
# The reason why the DST will only begin November 3rd is that the thousands
# of electoral machines used cannot have their time changed, and since the
# Constitution says the elections must begin at 8:00 AM and end at 5:00 PM,
# the Government decided to postpone DST, instead of changing the Constitution
# (maybe, for the next elections, it will be possible to change the clock)...
# From Rodrigo Severo (2004-10-04):
# It's just the biannual change made necessary by the much hyped, supposedly
# modern Brazilian eletronic voting machines which, apparently, can't deal
# with a time change between the first and the second rounds of the elections.
# From Steffen Thorsen (2007-09-20):
# Brazil will start DST on 2007-10-14 00:00 and end on 2008-02-17 00:00:
# From Paul Schulze (2008-06-24):
#
...by law number 11.662 of April 24, 2008 (published in the "Diario
# Oficial da Uniao"...) in Brazil there are changes in the timezones,
# effective today (00:00am at June 24, 2008) as follows:
# a) The timezone UTC+5 is e[x]tinguished, with all the Acre state and the
# part of the Amazonas state that had this timezone now being put to the
# b) The whole Para state now is put at timezone UTC+3, instead of just
# part of it, as was before.
# This change follows a proposal of senator Tiao Viana of Acre state, that
# proposed it due to concerns about open television channels displaying
# programs inappropriate to youths in the states that had the timezone
# UTC+5 too early in the night. In the occasion, some more corrections
# were proposed, trying to unify the timezones of any given state. This
# change modifies timezone rules defined in decree 2.784 of 18 June,
# From Rodrigo Severo (2008-06-24):
# Just correcting the URL:
# timezone shall be modified from UTC-5 to UTC-4 and a new timezone shall
# be created to represent
the...west side of the Para State. I
# suggest this new timezone be called Santarem as the most
# This new timezone would be the same as the Rio_Branco timezone up to
# the 2008/06/24 change which would be to UTC-3 instead of UTC-4.
# From Alex Krivenyshev (2008-06-24):
# This is a quick reference page for New and Old Brazil Time Zones map.
# - 4 time zones replaced by 3 time zones-eliminating time zone UTC- 05
# (state Acre and the part of the Amazonas will be
UTC/GMT- 04) - western
# part of Par state is moving to one timezone UTC- 03 (from UTC -04).
# From Paul Eggert (2002-10-10):
# The official decrees referenced below are mostly taken from
# Decretos sobre o Horario de Verao no Brasil
# From Steffen Thorsen (2008-08-29):
# As announced by the government and many newspapers in Brazil late
# yesterday, Brazil will start DST on 2008-10-19 (need to change rule) and
# it will end on 2009-02-15 (current rule for Brazil is fine). Based on
# past years experience with the elections, there was a good chance that
# the start was postponed to November, but it did not happen this year.
# An official page about it:
# Note that this link does not always work directly, but must be accessed
# One example link that works directly:
# We have a written a short article about it as well:
# From Alexander Krivenyshev (2011-10-04):
# State Bahia will return to Daylight savings time this year after 8 years off.
# The announcement was made by Governor Jaques Wagner in an interview to a
# television station in Salvador.
# From Guilherme Bernardes Rodrigues (2011-10-07):
# There is news in the media, however there is still no decree about it.
# I just send a e-mail to Zulmira Brandao at
# official agency about time in Brazil, and she confirmed that the old rule is
# From Guilherme Bernardes Rodrigues (2011-10-14)
# It's official, the President signed a decree that includes Bahia in summer
# [ and in a second message (same day): ]
# DECRETO No- 7.584, DE 13 DE OUTUBRO DE 2011
# From Kelley Cook (2012-10-16):
# The governor of state of Bahia in Brazil announced on Thursday that
# due to public pressure, he is reversing the DST policy they implemented
# last year and will not be going to Summer Time on October 21st....
# From Rodrigo Severo (2012-10-16):
# Tocantins state will have DST.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Brazil 1931 only - Oct 3 11:00 1:00 S
Rule Brazil 1932 1933 - Apr 1 0:00 0 -
Rule Brazil 1932 only - Oct 3 0:00 1:00 S
Rule Brazil 1949 1952 - Dec 1 0:00 1:00 S
Rule Brazil 1950 only - Apr 16 1:00 0 -
Rule Brazil 1951 1952 - Apr 1 0:00 0 -
Rule Brazil 1953 only - Mar 1 0:00 0 -
# established DST from 1963-10-23 00:00 to 1964-02-29 00:00
# in SP, RJ, GB, MG, ES, due to the prolongation of the drought.
# extended the above decree to all of the national territory on 12-09.
Rule Brazil 1963 only - Dec 9 0:00 1:00 S
# extended summer time by one day to 1964-03-01 00:00 (start of school).
Rule Brazil 1964 only - Mar 1 0:00 0 -
Rule Brazil 1965 only - Jan 31 0:00 1:00 S
Rule Brazil 1965 only - Mar 31 0:00 0 -
Rule Brazil 1965 only - Dec 1 0:00 1:00 S
Rule Brazil 1966 1968 - Mar 1 0:00 0 -
Rule Brazil 1966 1967 - Nov 1 0:00 1:00 S
Rule Brazil 1985 only - Nov 2 0:00 1:00 S
# Decree 92,310 (1986-01-21)
# Decree 92,463 (1986-03-13)
Rule Brazil 1986 only - Mar 15 0:00 0 -
# Decree 93,316 (1986-10-01)
Rule Brazil 1986 only - Oct 25 0:00 1:00 S
Rule Brazil 1987 only - Feb 14 0:00 0 -
Rule Brazil 1987 only - Oct 25 0:00 1:00 S
Rule Brazil 1988 only - Feb 7 0:00 0 -
# except for the states of AC, AM, PA, RR, RO, and AP (then a territory)
Rule Brazil 1988 only - Oct 16 0:00 1:00 S
Rule Brazil 1989 only - Jan 29 0:00 0 -
# with the same exceptions
Rule Brazil 1989 only - Oct 15 0:00 1:00 S
Rule Brazil 1990 only - Feb 11 0:00 0 -
# adopted by RS, SC, PR, SP, RJ, ES, MG, GO, MS, DF.
# Decree 99,629 (1990-10-19) adds BA, MT.
Rule Brazil 1990 only - Oct 21 0:00 1:00 S
Rule Brazil 1991 only - Feb 17 0:00 0 -
# adopted by RS, SC, PR, SP, RJ, ES, MG, BA, GO, MT, MS, DF.
Rule Brazil 1991 only - Oct 20 0:00 1:00 S
Rule Brazil 1992 only - Feb 9 0:00 0 -
# adopted by same states.
Rule Brazil 1992 only - Oct 25 0:00 1:00 S
Rule Brazil 1993 only - Jan 31 0:00 0 -
# adopted by same states, plus AM.
# web page corrected 2004-01-07) adopted by same states, minus AM.
# adopted by same states, plus MT and TO.
Rule Brazil 1993 1995 - Oct Sun>=11 0:00 1:00 S
Rule Brazil 1994 1995 - Feb Sun>=15 0:00 0 -
Rule Brazil 1996 only - Feb 11 0:00 0 -
# adopted by same states, minus AL, SE.
Rule Brazil 1996 only - Oct 6 0:00 1:00 S
Rule Brazil 1997 only - Feb 16 0:00 0 -
# From Daniel C. Sobral (1998-02-12):
# In 1997, the DS began on October 6. The stated reason was that
# because international television networks ignored Brazil's policy on DS,
# they bought the wrong times on satellite for coverage of Pope's visit.
# This year, the ending date of DS was postponed to March 1
# to help dealing with the shortages of electric power.
# Decree 2,317 (1997-09-04), adopted by same states.
Rule Brazil 1997 only - Oct 6 0:00 1:00 S
Rule Brazil 1998 only - Mar 1 0:00 0 -
# adopted by the same states as before.
Rule Brazil 1998 only - Oct 11 0:00 1:00 S
Rule Brazil 1999 only - Feb 21 0:00 0 -
# (1999-08-23) adopted by same states.
# adds SE, AL, PB, PE, RN, CE, PI, MA and RR.
Rule Brazil 1999 only - Oct 3 0:00 1:00 S
Rule Brazil 2000 only - Feb 27 0:00 0 -
# adopted by the same states as before.
# repeals DST in PE and RR, effective 2000-10-15 00:00.
# repeals DST in SE, AL, PB, RN, CE, PI and MA, effective 2000-10-22 00:00.
# (2001-09-13) reestablishes DST in AL, CE, MA, PB, PE, PI, RN, SE.
Rule Brazil 2000 2001 - Oct Sun>=8 0:00 1:00 S
Rule Brazil 2001 2006 - Feb Sun>=15 0:00 0 -
# Decree 4,399 (2002-10-01) repeals DST in AL, CE, MA, PB, PE, PI, RN, SE.
Rule Brazil 2002 only - Nov 3 0:00 1:00 S
# Decree 4,844 (2003-09-24; corrected 2003-09-26) repeals DST in BA, MT, TO.
Rule Brazil 2003 only - Oct 19 0:00 1:00 S
# Decree 5,223 (2004-10-01) reestablishes DST in MT.
Rule Brazil 2004 only - Nov 2 0:00 1:00 S
# adopted by the same states as before.
Rule Brazil 2005 only - Oct 16 0:00 1:00 S
# adopted by the same states as before.
Rule Brazil 2006 only - Nov 5 0:00 1:00 S
Rule Brazil 2007 only - Feb 25 0:00 0 -
# adopted by the same states as before.
Rule Brazil 2007 only - Oct Sun>=8 0:00 1:00 S
# From Frederico A. C. Neves (2008-09-10):
# Acording to this decree
# [t]he DST period in Brazil now on will be from the 3rd Oct Sunday to the
# 3rd Feb Sunday. There is an exception on the return date when this is
# the Carnival Sunday then the return date will be the next Sunday...
Rule Brazil 2008 max - Oct Sun>=15 0:00 1:00 S
Rule Brazil 2008 2011 - Feb Sun>=15 0:00 0 -
Rule Brazil 2012 only - Feb Sun>=22 0:00 0 -
Rule Brazil 2013 2014 - Feb Sun>=15 0:00 0 -
Rule Brazil 2015 only - Feb Sun>=22 0:00 0 -
Rule Brazil 2016 2022 - Feb Sun>=15 0:00 0 -
Rule Brazil 2023 only - Feb Sun>=22 0:00 0 -
Rule Brazil 2024 2025 - Feb Sun>=15 0:00 0 -
Rule Brazil 2026 only - Feb Sun>=22 0:00 0 -
Rule Brazil 2027 2033 - Feb Sun>=15 0:00 0 -
Rule Brazil 2034 only - Feb Sun>=22 0:00 0 -
Rule Brazil 2035 2036 - Feb Sun>=15 0:00 0 -
Rule Brazil 2037 only - Feb Sun>=22 0:00 0 -
# From Arthur David Olson (2008-09-29):
# The next is wrong in some years but is better than nothing.
Rule Brazil 2038 max - Feb Sun>=15 0:00 0 -
# The latest ruleset listed above says that the following states observe DST:
# DF, ES, GO, MG, MS, MT, PR, RJ, RS, SC, SP.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# Fernando de Noronha (administratively part of PE)
-2:00 Brazil FN%sT 1990 Sep 17
-2:00 Brazil FN%sT 2000 Oct 15
-2:00 Brazil FN%sT 2002 Oct 1
# Other Atlantic islands have no permanent settlement.
# These include Trindade and Martin Vaz (administratively part of ES),
# Atol das Rocas (RN), and Penedos de Sao Pedro e Sao Paulo (PE).
# Fernando de Noronha was a separate territory from 1942-09-02 to 1989-01-01;
# it also included the Penedos.
# Amapa (AP), east Para (PA)
# East Para includes Belem, Maraba, Serra Norte, and Sao Felix do Xingu.
# The division between east and west Para is the river Xingu.
# In the north a very small part from the river Javary (now Jari I guess,
# the border with Amapa) to the Amazon, then to the Xingu.
-3:00 Brazil BR%sT 1988 Sep 12
# West Para includes Altamira, Oribidos, Prainha, Oriximina, and Santarem.
-4:00 Brazil AM%sT 1988 Sep 12
-4:00 - AMT 2008 Jun 24 00:00
# Maranhao (MA), Piaui (PI), Ceara (CE), Rio Grande do Norte (RN),
-3:00 Brazil BR%sT 1990 Sep 17
-3:00 Brazil BR%sT 2000 Oct 22
-3:00 Brazil BR%sT 2002 Oct 1
# Pernambuco (PE) (except Atlantic islands)
-3:00 Brazil BR%sT 1990 Sep 17
-3:00 Brazil BR%sT 2000 Oct 15
-3:00 Brazil BR%sT 2002 Oct 1
-3:00 Brazil BR%sT 1990 Sep 17
-3:00 Brazil BR%sT 2003 Sep 24
# Alagoas (AL), Sergipe (SE)
-3:00 Brazil BR%sT 1990 Sep 17
-3:00 Brazil BR%sT 1996 Sep 4
-3:00 Brazil BR%sT 2000 Oct 22
-3:00 Brazil BR%sT 2002 Oct 1
# There are too many Salvadors elsewhere, so use
America/Bahia instead
-3:00 Brazil BR%sT 2003 Sep 24
-3:00 Brazil BR%sT 2012 Oct 21
# Goias (GO), Distrito Federal (DF), Minas Gerais (MG),
# Espirito Santo (ES), Rio de Janeiro (RJ), Sao Paulo (SP), Parana (PR),
# Santa Catarina (SC), Rio Grande do Sul (RS)
-3:00 Brazil BR%sT 1963 Oct 23 00:00
# Mato Grosso do Sul (MS)
-4:00 Brazil AM%sT 2003 Sep 24
-4:00 Brazil AM%sT 1988 Sep 12
-4:00 Brazil AM%sT 1988 Sep 12
-4:00 Brazil AM%sT 2000 Oct 15
# east Amazonas (AM): Boca do Acre, Jutai, Manaus, Floriano Peixoto
# The great circle line from Tabatinga to Porto Acre divides
# east from west Amazonas.
-4:00 Brazil AM%sT 1988 Sep 12
-4:00 Brazil AM%sT 1994 Sep 22
# west Amazonas (AM): Atalaia do Norte, Boca do Maoco, Benjamin Constant,
# Eirunepe, Envira, Ipixuna
-5:00 Brazil AC%sT 1988 Sep 12
-5:00 Brazil AC%sT 1994 Sep 22
-5:00 - ACT 2008 Jun 24 00:00
-5:00 Brazil AC%sT 1988 Sep 12
-5:00 - ACT 2008 Jun 24 00:00
# From Eduardo Krell (1995-10-19):
# The law says to switch to DST at midnight [24:00] on the second SATURDAY
# of October.... The law is the same for March and October.
# Because of the drought this year, the government decided to go into
# DST earlier (saturday 9/26 at 24:00). This is a one-time change only ...
# (unless there's another dry season next year, I guess).
# From Julio I. Pacheco Troncoso (1999-03-18):
# Because of the same drought, the government decided to end DST later,
# on April 3, (one-time change).
# From Oscar van Vlijmen (2006-10-08):
# From Jesper Norgaard Welen (2006-10-08):
# I think that there are some obvious mistakes in the suggested link
# from Oscar van Vlijmen,... for instance entry 66 says that GMT-4
# ended 1990-09-12 while entry 67 only begins GMT-3 at 1990-09-15
# (they should have been 1990-09-15 and 1990-09-16 respectively), but
# anyhow it clears up some doubts too.
# From Paul Eggert (2006-12-27):
# & Pottenger, except with DST transitions after 1932 cloned from
# but we have no other source.
# From German Poo-Caaman~o (2008-03-03):
# Due to drought, Chile extends Daylight Time in three weeks. This
# The Supreme Decree is located at
# and the instructions for 2008 are located in:
# From Jose Miguel Garrido (2008-03-05):
# You could see the announces of the change on
# From Angel Chiang (2010-03-04):
# Subject: DST in Chile exceptionally extended to 3 April due to earthquake
# (in Spanish, last paragraph).
# This is breaking news. There should be more information available later.
# From Arthur Daivd Olson (2010-03-06):
# Angel Chiang's message confirmed by Julio Pacheco; Julio provided a patch.
# From Glenn Eychaner (2011-03-02): [geychaner@mac.com]
# It appears that the Chilean government has decided to postpone the
# change from summer time to winter time again, by three weeks to April
# This is not yet reflected in the offical "cambio de hora" site, but
# From Arthur David Olson (2011-03-02):
# The
emol.com article mentions a water shortage as the cause of the
# postponement, which may mean that it's not a permanent change.
# From Glenn Eychaner (2011-03-28):
# Chile's clocks will go back an hour this year on the 7th of May instead
# of this Saturday. They will go forward again the 3rd Saturday in
# August, not in October as they have since 1968. This is a pilot plan
# which will be reevaluated in 2012.
# From Mauricio Parada (2012-02-22), translated by Glenn Eychaner (2012-02-23):
# As stated in the website of the Chilean Energy Ministry
# The Chilean Government has decided to postpone the entrance into winter time
# (to leave DST) from March 11 2012 to April 28th 2012. The decision has not
# been yet formalized but it will within the next days.
# Quote from the website communication:
# 6. For the year 2012, the dates of entry into winter time will be as follows:
# a. Saturday April 28, 2012, clocks should go back 60 minutes; that is, at
# 23:59:59, instead of passing to 0:00, the time should be adjusted to be 23:00
# b. Saturday, September 1, 2012, clocks should go forward 60 minutes; that is,
# at 23:59:59, instead of passing to 0:00, the time should be adjusted to be
# From Steffen Thorsen (2013-02-15):
# According to several news sources, Chile has extended DST this year,
# they will end DST later and start DST earlier than planned. They
# hope to save energy. The new end date is 2013-04-28 00:00 and new
# start date is 2013-09-08 00:00....
# NOTE: ChileAQ rules for Antarctic bases are stored separately in the
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Chile 1927 1932 - Sep 1 0:00 1:00 S
Rule Chile 1928 1932 - Apr 1 0:00 0 -
Rule Chile 1942 only - Jun 1 4:00u 0 -
Rule Chile 1942 only - Aug 1 5:00u 1:00 S
Rule Chile 1946 only - Jul 15 4:00u 1:00 S
Rule Chile 1946 only - Sep 1 3:00u 0:00 -
Rule Chile 1947 only - Apr 1 4:00u 0 -
Rule Chile 1968 only - Nov 3 4:00u 1:00 S
Rule Chile 1969 only - Mar 30 3:00u 0 -
Rule Chile 1969 only - Nov 23 4:00u 1:00 S
Rule Chile 1970 only - Mar 29 3:00u 0 -
Rule Chile 1971 only - Mar 14 3:00u 0 -
Rule Chile 1970 1972 - Oct Sun>=9 4:00u 1:00 S
Rule Chile 1972 1986 - Mar Sun>=9 3:00u 0 -
Rule Chile 1973 only - Sep 30 4:00u 1:00 S
Rule Chile 1974 1987 - Oct Sun>=9 4:00u 1:00 S
Rule Chile 1987 only - Apr 12 3:00u 0 -
Rule Chile 1988 1989 - Mar Sun>=9 3:00u 0 -
Rule Chile 1988 only - Oct Sun>=1 4:00u 1:00 S
Rule Chile 1989 only - Oct Sun>=9 4:00u 1:00 S
Rule Chile 1990 only - Mar 18 3:00u 0 -
Rule Chile 1990 only - Sep 16 4:00u 1:00 S
Rule Chile 1991 1996 - Mar Sun>=9 3:00u 0 -
Rule Chile 1991 1997 - Oct Sun>=9 4:00u 1:00 S
Rule Chile 1997 only - Mar 30 3:00u 0 -
Rule Chile 1998 only - Mar Sun>=9 3:00u 0 -
Rule Chile 1998 only - Sep 27 4:00u 1:00 S
Rule Chile 1999 only - Apr 4 3:00u 0 -
Rule Chile 1999 2010 - Oct Sun>=9 4:00u 1:00 S
Rule Chile 2000 2007 - Mar Sun>=9 3:00u 0 -
#
N.B.: the end of March 29 in Chile is March 30 in Universal time,
# which is used below in specifying the transition.
Rule Chile 2008 only - Mar 30 3:00u 0 -
Rule Chile 2009 only - Mar Sun>=9 3:00u 0 -
Rule Chile 2010 only - Apr Sun>=1 3:00u 0 -
Rule Chile 2011 only - May Sun>=2 3:00u 0 -
Rule Chile 2011 only - Aug Sun>=16 4:00u 1:00 S
Rule Chile 2012 max - Apr Sun>=23 3:00u 0 -
Rule Chile 2012 max - Sep Sun>=2 4:00u 1:00 S
# IATA SSIM anomalies: (1992-02) says 1992-03-14;
# (1996-09) says 1998-03-08. Ignore these.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:42:46 - SMT 1910 # Santiago Mean Time
-5:00 - CLT 1916 Jul 1 # Chile Time
-4:42:46 - SMT 1918 Sep 1 # Santiago Mean Time
-4:00 - CLT 1919 Jul 1 # Chile Time
-4:42:46 - SMT 1927 Sep 1 # Santiago Mean Time
-5:00 Chile CL%sT 1947 May 22 # Chile Time
-7:17:28 - EMT 1932 Sep # Easter Mean Time
-7:00 Chile EAS%sT 1982 Mar 13 21:00 # Easter I Time
# Other Chilean locations, including Juan Fernandez Is, San Ambrosio,
# Milne gives 4:56:16.4 for Bogota time in 1899; round to nearest. He writes,
# "A variation of fifteen minutes in the public clocks of Bogota is not rare."
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule CO 1992 only - May 3 0:00 1:00 S
Rule CO 1993 only - Apr 4 0:00 0 -
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:56:16 - BMT 1914 Nov 23 # Bogota Mean Time
-5:00 CO CO%sT # Colombia Time
# Malpelo, Providencia, San Andres
# Milne gives 4:35:46.9 for Curacao mean time; round to nearest.
# From Paul Eggert (2006-03-22):
# Shanks & Pottenger say that The Bottom and Philipsburg have been at
# -4:00 since standard time was introduced on 1912-03-02; and that
# Kralendijk and Rincon used Kralendijk Mean Time (-4:33:08) from
# 1912-02-02 to 1965-01-01. The former is dubious, since S&P also say
# Saba Island has been like Curacao.
# This all predates our 1970 cutoff, though.
# By July 2007 Curacao and St Maarten are planned to become
# associated states within the Netherlands, much like Aruba;
# Bonaire, Saba and St Eustatius would become directly part of the
# Netherlands as Kingdom Islands. This won't affect their time zones
# though, as far as we know.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:30 - ANT 1965 # Netherlands Antilles Time
# From Arthur David Olson (2011-06-15):
# At least for now, use links for places with new iso3166 codes.
# The name "Lower Prince's Quarter" is both longer than fourteen charaters
# and contains an apostrophe; use "Lower_Princes" below.
# Milne says the Sentral and South American Telegraph Company used -5:24:15.
# From Paul Eggert (2007-03-04):
# Apparently Ecuador had a failed experiment with DST in 1992.
# talk about "hora Sixto". Leave this alone for now, as we have no data.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-5:14:00 - QMT 1931 # Quito Mean Time
-5:00 - ECT # Ecuador Time
-6:00 - GALT # Galapagos Time
# From Paul Eggert (2006-03-22):
# Between 1990 and 2000 inclusive, Shanks & Pottenger and the IATA agree except
# the IATA gives 1996-09-08. Go with Shanks & Pottenger.
# From Falkland Islands Government Office, London (2001-01-22)
# ... the clocks revert back to Local Mean Time at 2 am on Sunday 15
# April 2001 and advance one hour to summer time at 2 am on Sunday 2
# September. It is anticipated that the clocks will revert back at 2
# am on Sunday 21 April 2002 and advance to summer time at 2 am on
# From Rives McDow (2001-02-13):
# I have communicated several times with people there, and the last
# time I had communications that was helpful was in 1998. Here is
# "The general rule was that Stanley used daylight saving and the Camp
# did not. However for various reasons many people in the Camp have
# started to use daylight saving (known locally as 'Stanley Time')
# There is no rule as to who uses daylight saving - it is a matter of
# personal choice and so it is impossible to draw a map showing who
# uses it and who does not. Any list would be out of date as soon as
# it was produced. This year daylight saving ended on April 18/19th
# and started again on September 12/13th. I do not know what the rule
# is, but can find out if you like. We do not change at the same time
# I did have in my notes that the rule was "Second Saturday in Sep at
# 0:00 until third Saturday in Apr at 0:00". I think that this does
# not agree in some cases with Shanks; is this true?
# Also, there is no mention in the list that some areas in the
# Falklands do not use DST. I have found in my communications there
# that these areas are on the western half of East Falkland and all of
# West Falkland. Stanley is the only place that consistently observes
# DST. Again, as in other places in the world, the farmers don't like
# it. West Falkland is almost entirely sheep farmers.
# I know one lady there that keeps a list of which farm keeps DST and
# which doesn't each year. She runs a shop in Stanley, and says that
# the list changes each year. She uses it to communicate to her
# customers, catching them when they are home for lunch or dinner.
# From Paul Eggert (2001-03-05):
# For now, we'll just record the time in Stanley, since we have no
# From Steffen Thorsen (2011-04-01):
# The Falkland Islands will not turn back clocks this winter, but stay on
# We have gotten this confirmed by a clerk of the legislative assembly:
# Normally the clocks revert to Local Mean Time (
UTC/GMT -4 hours) on the
# third Sunday of April at 0200hrs and advance to Summer Time (
UTC/GMT -3
# hours) on the first Sunday of September at 0200hrs.
# IMPORTANT NOTE: During 2011, on a trial basis, the Falkland Islands
# will not revert to local mean time, but clocks will remain on Summer
# time (
UTC/GMT - 3 hours) throughout the whole of 2011. Any long term
# change to local time following the trial period will be notified.
# From Andrew Newman (2012-02-24)
# A letter from Justin McPhee, Chief Executive,
# Cable & Wireless Falkland Islands (dated 2012-02-22)
# clocks to go back to standard Falklands Time (FKT) on the 15th April.
# The database entry states that in 2011 Stanley was staying on fixed
# summer time on a trial basis only. FIG need to contact IANA
and/or# the maintainers of the database to inform them we're adopting
# the same policy this year and suggest recommendations for future years.
# For now we will assume permanent summer time for the Falklands
# until advised differently (to apply for 2012 and beyond, after the 2011
# experiment was apparently successful.)
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Falk 1937 1938 - Sep lastSun 0:00 1:00 S
Rule Falk 1938 1942 - Mar Sun>=19 0:00 0 -
Rule Falk 1939 only - Oct 1 0:00 1:00 S
Rule Falk 1940 1942 - Sep lastSun 0:00 1:00 S
Rule Falk 1943 only - Jan 1 0:00 0 -
Rule Falk 1983 only - Sep lastSun 0:00 1:00 S
Rule Falk 1984 1985 - Apr lastSun 0:00 0 -
Rule Falk 1984 only - Sep 16 0:00 1:00 S
Rule Falk 1985 2000 - Sep Sun>=9 0:00 1:00 S
Rule Falk 1986 2000 - Apr Sun>=16 0:00 0 -
Rule Falk 2001 2010 - Apr Sun>=15 2:00 0 -
Rule Falk 2001 2010 - Sep Sun>=1 2:00 1:00 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-3:51:24 - SMT 1912 Mar 12 # Stanley Mean Time
-4:00 Falk FK%sT 1983 May # Falkland Is Time
-3:00 Falk FK%sT 1985 Sep 15
-4:00 Falk FK%sT 2010 Sep 5 02:00
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:00 - GFT 1967 Oct # French Guiana Time
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-3:45 - GBGT 1966 May 26 # Br Guiana Time
-3:45 - GYT 1975 Jul 31 # Guyana Time
# IATA SSIM (1996-06) says -4:00. Assume a 1991 switch.
# From Paul Eggert (2006-03-22):
# Shanks & Pottenger say that spring transitions are from 01:00 -> 02:00,
# and autumn transitions are from 00:00 -> 23:00. Go with pre-1999
# editions of Shanks, and with the IATA, who say transitions occur at 00:00.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Para 1975 1988 - Oct 1 0:00 1:00 S
Rule Para 1975 1978 - Mar 1 0:00 0 -
Rule Para 1979 1991 - Apr 1 0:00 0 -
Rule Para 1989 only - Oct 22 0:00 1:00 S
Rule Para 1990 only - Oct 1 0:00 1:00 S
Rule Para 1991 only - Oct 6 0:00 1:00 S
Rule Para 1992 only - Mar 1 0:00 0 -
Rule Para 1992 only - Oct 5 0:00 1:00 S
Rule Para 1993 only - Mar 31 0:00 0 -
Rule Para 1993 1995 - Oct 1 0:00 1:00 S
Rule Para 1994 1995 - Feb lastSun 0:00 0 -
Rule Para 1996 only - Mar 1 0:00 0 -
# IATA SSIM (2000-02) says 1999-10-10; ignore this for now.
# From Steffen Thorsen (2000-10-02):
# I have three independent reports that Paraguay changed to DST this Sunday
# Translated by Gwillim Law (2001-02-27) from
# Noticias, a daily paper in Asuncion, Paraguay (2000-10-01)
# Starting at 0:00 today, the clock will be set forward 60 minutes, in
# fulfillment of Decree No. 7,273 of the Executive Power.... The time change
# system has been operating for several years. Formerly there was a separate
# decree each year; the new law has the same effect, but permanently. Every
# year, the time will change on the first Sunday of October; likewise, the
# clock will be set back on the first Sunday of March.
Rule Para 1996 2001 - Oct Sun>=1 0:00 1:00 S
# IATA SSIM (1997-09) says Mar 1; go with Shanks & Pottenger.
Rule Para 1997 only - Feb lastSun 0:00 0 -
# Shanks & Pottenger say 1999-02-28; IATA SSIM (1999-02) says 1999-02-27, but
# (1999-09) reports no date; go with above sources and Gerd Knops (2001-02-27).
Rule Para 1998 2001 - Mar Sun>=1 0:00 0 -
# From Rives McDow (2002-02-28):
# A decree was issued in Paraguay (no. 16350) on 2002-02-26 that changed the
# dst method to be from the first Sunday in September to the first Sunday in
Rule Para 2002 2004 - Apr Sun>=1 0:00 0 -
Rule Para 2002 2003 - Sep Sun>=1 0:00 1:00 S
# From Jesper Norgaard Welen (2005-01-02):
# There are several sources that claim that Paraguay made
# a timezone rule change in autumn 2004.
# From Steffen Thorsen (2005-01-05):
# Decree 1,867 (2004-03-05)
# From Carlos Raul Perasso via Jesper Norgaard Welen (2006-10-13)
Rule Para 2004 2009 - Oct Sun>=15 0:00 1:00 S
Rule Para 2005 2009 - Mar Sun>=8 0:00 0 -
# From Carlos Raul Perasso (2010-02-18):
# By decree number 3958 issued yesterday (
# Paraguay changes its DST schedule, postponing the March rule to April and
# modifying the October date. The decree reads:
# Art. 1. It is hereby established that from the second Sunday of the month of
# April of this year (2010), the official time is to be set back 60 minutes,
# and that on the first Sunday of the month of October, it is to be set
# forward 60 minutes, in all the territory of the Paraguayan Republic.
Rule Para 2010 max - Oct Sun>=1 0:00 1:00 S
Rule Para 2010 2012 - Apr Sun>=8 0:00 0 -
# From Steffen Thorsen (2013-03-07):
# Paraguay will end DST on 2013-03-24 00:00....
# From Carlos Raul Perasso (2013-03-15):
# The change in Paraguay is now final. Decree number 10780
Rule Para 2013 max - Mar Sun>=22 0:00 0 -
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-3:50:40 - AMT 1931 Oct 10 # Asuncion Mean Time
-4:00 - PYT 1972 Oct # Paraguay Time
# <a href="news:xrGmb.39935$gA1.13896113@news4.srv.hcvlny.cv.net">
# From Evelyn C. Leeper via Mark Brader (2003-10-26):</a>
# When we were in Peru in 1985-1986, they apparently switched over
# sometime between December 29 and January 3 while we were on the Amazon.
# From Paul Eggert (2006-03-22):
# Shanks & Pottenger don't have this transition. Assume 1986 was like 1987.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Peru 1938 only - Jan 1 0:00 1:00 S
Rule Peru 1938 only - Apr 1 0:00 0 -
Rule Peru 1938 1939 - Sep lastSun 0:00 1:00 S
Rule Peru 1939 1940 - Mar Sun>=24 0:00 0 -
Rule Peru 1986 1987 - Jan 1 0:00 1:00 S
Rule Peru 1986 1987 - Apr 1 0:00 0 -
Rule Peru 1990 only - Jan 1 0:00 1:00 S
Rule Peru 1990 only - Apr 1 0:00 0 -
# IATA is ambiguous for 1993/1995; go with Shanks & Pottenger.
Rule Peru 1994 only - Jan 1 0:00 1:00 S
Rule Peru 1994 only - Apr 1 0:00 0 -
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-5:08:36 - LMT 1908 Jul 28 # Lima Mean Time?
-5:00 Peru PE%sT # Peru Time
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-2:00 - GST # South Georgia Time
# uninhabited; scientific personnel have wintered
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-3:40:52 - PMT 1935 # Paramaribo Mean Time
-3:40:36 - PMT 1945 Oct # The capital moved?
-3:30 - NEGT 1975 Nov 20 # Dutch Guiana Time
-3:30 - SRT 1984 Oct # Suriname Time
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
# From Paul Eggert (1993-11-18):
# Uruguay wins the prize for the strangest peacetime manipulation of the rules.
# From Shanks & Pottenger:
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
# Whitman gives 1923 Oct 1; go with Shanks & Pottenger.
Rule Uruguay 1923 only - Oct 2 0:00 0:30 HS
Rule Uruguay 1924 1926 - Apr 1 0:00 0 -
Rule Uruguay 1924 1925 - Oct 1 0:00 0:30 HS
Rule Uruguay 1933 1935 - Oct lastSun 0:00 0:30 HS
# Shanks & Pottenger give 1935 Apr 1 0:00 & 1936 Mar 30 0:00; go with Whitman.
Rule Uruguay 1934 1936 - Mar Sat>=25 23:30s 0 -
Rule Uruguay 1936 only - Nov 1 0:00 0:30 HS
Rule Uruguay 1937 1941 - Mar lastSun 0:00 0 -
# Whitman gives 1937 Oct 3; go with Shanks & Pottenger.
Rule Uruguay 1937 1940 - Oct lastSun 0:00 0:30 HS
# Whitman gives 1941 Oct 24 - 1942 Mar 27, 1942 Dec 14 - 1943 Apr 13,
# and 1943 Apr 13 ``to present time''; go with Shanks & Pottenger.
Rule Uruguay 1941 only - Aug 1 0:00 0:30 HS
Rule Uruguay 1942 only - Jan 1 0:00 0 -
Rule Uruguay 1942 only - Dec 14 0:00 1:00 S
Rule Uruguay 1943 only - Mar 14 0:00 0 -
Rule Uruguay 1959 only - May 24 0:00 1:00 S
Rule Uruguay 1959 only - Nov 15 0:00 0 -
Rule Uruguay 1960 only - Jan 17 0:00 1:00 S
Rule Uruguay 1960 only - Mar 6 0:00 0 -
Rule Uruguay 1965 1967 - Apr Sun>=1 0:00 1:00 S
Rule Uruguay 1965 only - Sep 26 0:00 0 -
Rule Uruguay 1966 1967 - Oct 31 0:00 0 -
Rule Uruguay 1968 1970 - May 27 0:00 0:30 HS
Rule Uruguay 1968 1970 - Dec 2 0:00 0 -
Rule Uruguay 1972 only - Apr 24 0:00 1:00 S
Rule Uruguay 1972 only - Aug 15 0:00 0 -
Rule Uruguay 1974 only - Mar 10 0:00 0:30 HS
Rule Uruguay 1974 only - Dec 22 0:00 1:00 S
Rule Uruguay 1976 only - Oct 1 0:00 0 -
Rule Uruguay 1977 only - Dec 4 0:00 1:00 S
Rule Uruguay 1978 only - Apr 1 0:00 0 -
Rule Uruguay 1979 only - Oct 1 0:00 1:00 S
Rule Uruguay 1980 only - May 1 0:00 0 -
Rule Uruguay 1987 only - Dec 14 0:00 1:00 S
Rule Uruguay 1988 only - Mar 14 0:00 0 -
Rule Uruguay 1988 only - Dec 11 0:00 1:00 S
Rule Uruguay 1989 only - Mar 12 0:00 0 -
Rule Uruguay 1989 only - Oct 29 0:00 1:00 S
# Shanks & Pottenger say no DST was observed in 1990/1 and 1991/2,
# and that 1992/3's DST was from 10-25 to 03-01. Go with IATA.
Rule Uruguay 1990 1992 - Mar Sun>=1 0:00 0 -
Rule Uruguay 1990 1991 - Oct Sun>=21 0:00 1:00 S
Rule Uruguay 1992 only - Oct 18 0:00 1:00 S
Rule Uruguay 1993 only - Feb 28 0:00 0 -
# From Eduardo Cota (2004-09-20):
# The uruguayan government has decreed a change in the local time....
Rule Uruguay 2004 only - Sep 19 0:00 1:00 S
# From Steffen Thorsen (2005-03-11):
# Uruguay's DST was scheduled to end on Sunday, 2005-03-13, but in order to
# save energy ... it was postponed two weeks....
Rule Uruguay 2005 only - Mar 27 2:00 0 -
# From Eduardo Cota (2005-09-27):
# This means that from 2005-10-09 at 02:00 local time, until 2006-03-12 at
# 02:00 local time, official time in Uruguay will be at GMT -2.
Rule Uruguay 2005 only - Oct 9 2:00 1:00 S
Rule Uruguay 2006 only - Mar 12 2:00 0 -
# From Jesper Norgaard Welen (2006-09-06):
Rule Uruguay 2006 max - Oct Sun>=1 2:00 1:00 S
Rule Uruguay 2007 max - Mar Sun>=8 2:00 0 -
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-3:44:44 - MMT 1920 May 1 # Montevideo MT
-3:30 Uruguay UY%sT 1942 Dec 14 # Uruguay Time
# From John Stainforth (2007-11-28):
# ... the change for Venezuela originally expected for 2007-12-31 has
# been brought forward to 2007-12-09. The official announcement was
# published today in the "Gaceta Oficial de la Republica Bolivariana
# de Venezuela, numero 38.819" (official document for all laws or
# resolution publication)
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
-4:27:40 - CMT 1912 Feb 12 # Caracas Mean Time?
-4:30 - VET 1965 # Venezuela Time
-4:00 - VET 2007 Dec 9 03:00