# @(#)southamerica 7.60
# 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 (1999-07-07):
# A good source for time zone historical data outside the U.S. is
# Thomas G. Shanks, The International Atlas (5th edition),
# San Diego: ACS Publications, Inc. (1999).
#
# 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 is the source for entries through 1990,
# and IATA SSIM is the source for entries after 1990.
#
# Earlier editions of these tables used the North American style (e.g. ARST and
# ARDT for Argentine Standard and Daylight Time), but the following quote
# suggests that it's better to use European style (e.g. ART and ARST).
# I suggest the use of _Summer time_ instead of the more cumbersome
# _daylight-saving time_. _Summer time_ seems to be in general use
# in Europe and South America.
# -- E O Cutler, _New York Times_ (1937-02-14), quoted in
# H L Mencken, _The American Language: Supplement I_ (1960), p 466
#
# Earlier editions of these tables also used the North American style
# for time zones in Brazil, but this was incorrect, as Brazilians say
# "summer time". Reinaldo Goulart, a Sao Paulo businessman active in
# the railroad sector, writes (1999-07-06):
# The subject of time zones is currently a matter of discussion/debate in
# Brazil. Let's say that "the Brasilia time" is considered the
# "official time" because Brasilia is the capital city.
# The other three time zones are called "Brasilia time "minus one" or
# "plus one" or "plus two". As far as I know there is no such
# name/designation as "Eastern Time" or "Central Time".
# So I invented the following (English-language) abbreviations for now.
# Corrections are welcome!
# std dst
# -2:00 FNT FNST Fernando de Noronha
# -3:00 BRT BRST Brasilia
# -4:00 AMT AMST Amazon
# -5:00 ACT ACST Acre
###############################################################################
###############################################################################
# Argentina
# From Bob Devine (1988-01-28):
# Argentina: first Sunday in October to first Sunday in April since 1976.
# Double Summer time from 1969 to 1974. Switches at midnight.
# From U. S. Naval Observatory (1988-01-199):
# ARGENTINA 3 H BEHIND UTC
# From Hernan G. Otero (1995-06-26):
# I am sending modifications to the Argentine time zone table...
# AR was chosen because they are the ISO letters that represent Argentina.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Arg 1930 only - Dec 1 0:00 1:00 S
Rule Arg 1931 only - Apr 1 0:00 0 -
Rule Arg 1931 only - Oct 15 0:00 1:00 S
Rule Arg 1932 1940 - Mar 1 0:00 0 -
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)
#
# Shanks stops after 1992-03-01; go with Otero.
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
Rule Arg 2000 only - Mar Sun>=1 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
# http://ar.clarin.com/diario/2001-06-06/e-01701.htm
# ... 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:
# http://www.boletin.jus.gov.ar/BON/Primera/1999/09-Septiembre/21/PDF/BO21-09-99LEG.PDF
# Regretfully, you have to subscribe (and pay) for the on-line version....
#
# (2001-06-12):
# the timezone for Argentina will not change next Sunday.
# Apparently it will do so on Sunday 24th....
# http://ar.clarin.com/diario/2001-06-12/s-03501.htm
#
# (2001-06-25):
# 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.
# http://www.clarin.com.ar/diario/2001-06-22/s-03601.htm
# 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 Mariano Absatz (2004-05-21):
# Today it was officially published that the Province of Mendoza is changing
# its timezone this winter... starting tomorrow night....
# http://www.gobernac.mendoza.gov.ar/boletin/pdf/20040521-27158-normas.pdf
# 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 (2002-01-22):
#
# Hora de verano para la Republica Argentina (2000-10-01)
# 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.
#
# From Mariano Absatz (2004-06-05):
# These media articles from a major newspaper mostly cover the current state:
# http://www.lanacion.com.ar/04/05/27/de_604825.asp
# http://www.lanacion.com.ar/04/05/28/de_605203.asp
#
# 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
# time in October 17th.
#
# 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):
# http://www.lanacion.com.ar/04/06/10/de_609078.asp ...
# "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).
# http://www.gobernac.mendoza.gov.ar/boletin/pdf/20040924-27244-normas.pdf
#
# 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....
# http://www.sanjuan.gov.ar/prensa/archivo/000329.html
# http://www.sanjuan.gov.ar/prensa/archivo/000426.html
# http://www.sanjuan.gov.ar/prensa/archivo/000441.html
# Unless otherwise specified, data are from Shanks through 1992, from
# the IATA otherwise. As noted below, Shanks says that
# America/Cordoba split into 6 subregions during 1991/1992, but we
# haven't verified this yet so for now we'll keep it a single region.
#
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
#
# Buenos Aires (BA), Capital Federal (CF),
Zone America/Argentina/Buenos_Aires -3:53:48 - LMT 1894 Oct 31
-4:16:48 - CMT 1920 May # Cordoba Mean Time
-4:00 - ART 1930 Dec
-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 - ART
#
# Santa Fe (SF), Entre Rios (ER), Corrientes (CN), Misiones (MN), Chaco (CC),
# Formosa (FM), Salta (SA), Santiago del Estero (SE), Cordoba (CB),
# San Luis (SL), La Pampa (LP), Neuquen (NQ), Rio Negro (RN)
#
# Shanks also makes 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.
# - San Luis switched to -4:00 on 1990-03-14, then to -3:00 on 1990-10-15,
# then to -4:00 on 1991-03-01, then to -3:00 on 1991-06-01.
# - Santiago del Estero switched to -4:00 on 1991-04-01,
# then to -3:00 on 1991-04-26.
#
Zone America/Argentina/Cordoba -4:16:48 - LMT 1894 Oct 31
-4:16:48 - CMT 1920 May
-4:00 - ART 1930 Dec
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Mar 3
-4:00 - WART 1991 Oct 20
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 - ART
#
# Tucuman (TM)
Zone America/Argentina/Tucuman -4:20:52 - LMT 1894 Oct 31
-4:16:48 - CMT 1920 May
-4:00 - ART 1930 Dec
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Mar 3
-4:00 - WART 1991 Oct 20
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 - ART 2004 Jun 1
-4:00 - WART 2004 Jun 13
-3:00 - ART
#
# La Rioja (LR)
Zone America/Argentina/La_Rioja -4:27:24 - LMT 1894 Oct 31
-4:16:48 - CMT 1920 May
-4:00 - ART 1930 Dec
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Mar 1
-4:00 - WART 1991 May 7
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 - ART 2004 Jun 1
-4:00 - WART 2004 Jun 20
-3:00 - ART
#
# San Juan (SJ)
Zone America/Argentina/San_Juan -4:34:04 - LMT 1894 Oct 31
-4:16:48 - CMT 1920 May
-4:00 - ART 1930 Dec
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Mar 1
-4:00 - WART 1991 May 7
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 - ART 2004 May 31
-4:00 - WART 2004 Jul 25
-3:00 - ART
#
# Jujuy (JY)
Zone America/Argentina/Jujuy -4:21:12 - LMT 1894 Oct 31
-4:16:48 - CMT 1920 May
-4:00 - ART 1930 Dec
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1990 Mar 4
-4:00 - WART 1990 Oct 28
-4:00 1:00 WARST 1991 Mar 17
-4:00 - WART 1991 Oct 6
-3:00 1:00 ARST 1992
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 - ART
#
# Catamarca (CT)
Zone America/Argentina/Catamarca -4:23:08 - LMT 1894 Oct 31
-4:16:48 - CMT 1920 May
-4:00 - ART 1930 Dec
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Mar 3
-4:00 - WART 1991 Oct 20
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 - ART 2004 Jun 1
-4:00 - WART 2004 Jun 20
-3:00 - ART
#
# Mendoza (MZ)
Zone America/Argentina/Mendoza -4:35:16 - LMT 1894 Oct 31
-4:16:48 - CMT 1920 May
-4:00 - ART 1930 Dec
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1990 Mar 4
-4:00 - WART 1990 Oct 15
-4:00 1:00 WARST 1991 Mar 1
-4:00 - WART 1991 Oct 15
-4:00 1:00 WARST 1992 Mar 1
-4:00 - WART 1992 Oct 18
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 - ART 2004 May 23
-4:00 - WART 2004 Sep 26
-3:00 - ART
#
# Chubut (CH)
# The name "Comodoro Rivadavia" exceeds the 14-byte POSIX limit.
Zone America/Argentina/ComodRivadavia -4:30:00 - LMT 1894 Oct 31
-4:16:48 - CMT 1920 May
-4:00 - ART 1930 Dec
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Mar 3
-4:00 - WART 1991 Oct 20
-3:00 Arg AR%sT 1999 Oct 3
-4:00 Arg AR%sT 2000 Mar 3
-3:00 - ART 2004 Jun 1
-4:00 - WART 2004 Jun 20
-3:00 - ART
#
# Santa Cruz (SC)
Zone America/Argentina/Rio_Gallegos -4:36:52 - LMT 1894 Oct 31
-4:16:48 - CMT 1920 May # Cordoba Mean Time
-4:00 - ART 1930 Dec
-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 - ART 2004 Jun 1
-4:00 - WART 2004 Jun 20
-3:00 - ART
#
# Tierra del Fuego, Antartida e Islas del Atlantico Sur (TF)
Zone America/Argentina/Ushuaia -4:33:12 - LMT 1894 Oct 31
-4:16:48 - CMT 1920 May # Cordoba Mean Time
-4:00 - ART 1930 Dec
-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 - ART 2004 May 30
-4:00 - WART 2004 Jun 20
-3:00 - ART
# Aruba
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Aruba -4:40:24 - LMT 1912 Feb 12 # Oranjestad
-4:30 - ANT 1965 # Netherlands Antilles Time
-4:00 - AST
# Bolivia
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/La_Paz -4:32:36 - LMT 1890
-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
# Brazil
# 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:]
# http://pcdsh01.on.br/Fusbr.htm
# http://pcdsh01.on.br/Fusbrhv.htm
# 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 Paul Eggert (2002-10-10):
# The official decrees referenced below are mostly taken from
#
# Decretos sobre o Horario de Verao no Brasil
# (2001-09-20, in Portuguese).
# The official site for all decrees, including those not related to time, is
#
# Presidencia da Republica, Subchefia para Assuntos Juridicos, Decretos
# (in Portuguese).
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
# Decree 20,466 (1931-10-01)
# Decree 21,896 (1932-01-10)
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
# Decree 23,195 (1933-10-10)
# revoked DST.
# Decree 27,496 (1949-11-24)
# Decree 27,998 (1950-04-13)
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 -
# Decree 32,308 (1953-02-24)
Rule Brazil 1953 only - Mar 1 0:00 0 -
# Decree 34,724 (1953-11-30)
# revoked DST.
# Decree 52,700 (1963-10-18)
# 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.
# Decree 53,071 (1963-12-03)
# extended the above decree to all of the national territory on 12-09.
Rule Brazil 1963 only - Dec 9 0:00 1:00 S
# Decree 53,604 (1964-02-25)
# extended summer time by one day to 1964-03-01 00:00 (start of school).
Rule Brazil 1964 only - Mar 1 0:00 0 -
# Decree 55,639 (1965-01-27)
Rule Brazil 1965 only - Jan 31 0:00 1:00 S
Rule Brazil 1965 only - Mar 31 0:00 0 -
# Decree 57,303 (1965-11-22)
Rule Brazil 1965 only - Dec 1 0:00 1:00 S
# Decree 57,843 (1966-02-18)
Rule Brazil 1966 1968 - Mar 1 0:00 0 -
Rule Brazil 1966 1967 - Nov 1 0:00 1:00 S
# Decree 63,429 (1968-10-15)
# revoked DST.
# Decree 91,698 (1985-09-27)
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 -
# Decree 94,922 (1987-09-22)
Rule Brazil 1987 only - Oct 25 0:00 1:00 S
Rule Brazil 1988 only - Feb 7 0:00 0 -
# Decree 96,676 (1988-09-12)
# 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 -
# Decree 98,077 (1989-08-21)
# with the same exceptions
Rule Brazil 1989 only - Oct 15 0:00 1:00 S
Rule Brazil 1990 only - Feb 11 0:00 0 -
# Decree 99,530 (1990-09-17)
# 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 -
# Unnumbered decree (1991-09-25)
# 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 -
# Unnumbered decree (1992-10-16)
# adopted by same states.
Rule Brazil 1992 only - Oct 25 0:00 1:00 S
Rule Brazil 1993 only - Jan 31 0:00 0 -
# Decree 942 (1993-09-28)
# adopted by same states, plus AM.
# Decree 1,252 (1994-09-22;
# web page corrected 2004-01-07) adopted by same states, minus AM.
# Decree 1,636 (1995-09-14)
# adopted by same states, plus MT and TO.
# Decree 1,674 (1995-10-13)
# adds AL, SE.
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 -
# Decree 2,000 (1996-09-04)
# 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.
#
# From Paul Eggert (1998-02-25):
#
# Brazil Prepares for Papal Visit
# ,
# Church Net UK (1997-10-02).
#
# Decree 2,317 (1997-09-04), adopted by same states.
Rule Brazil 1997 only - Oct 6 0:00 1:00 S
# Decree 2,495
# (1998-02-10)
Rule Brazil 1998 only - Mar 1 0:00 0 -
# Decree 2,780 (1998-09-11)
# 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 -
# Decree 3,150
# (1999-08-23) adopted by same states.
# Decree 3,188 (1999-09-30)
# 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 -
# Decree 3,592 (2000-09-06)
# adopted by the same states as before.
# Decree 3,630 (2000-10-13)
# repeals DST in PE and RR, effective 2000-10-15 00:00.
# Decree 3,632 (2000-10-17)
# repeals DST in SE, AL, PB, RN, CE, PI and MA, effective 2000-10-22 00:00.
# Decree 3,916
# (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 max - 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
# The latest ruleset listed above says that the following states observe DST:
# DF, ES, GO, MG, MS, MT, PR, RJ, RS, SC, SP.
#
Rule Brazil 2005 max - Oct Sun>=15 0:00 1:00 S
# For dates after mid-2005, the above rules with TO="max" are guesses
# and are quite possibly wrong, but are more likely than no DST at all.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
#
# Fernando de Noronha (administratively part of PE)
Zone America/Noronha -2:09:40 - LMT 1914
-2:00 Brazil FN%sT 1990 Sep 17
-2:00 - FNT 1999 Sep 30
-2:00 Brazil FN%sT 2000 Oct 15
-2:00 - FNT 2001 Sep 13
-2:00 Brazil FN%sT 2002 Oct 1
-2:00 - FNT
# 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.
Zone America/Belem -3:13:56 - LMT 1914
-3:00 Brazil BR%sT 1988 Sep 12
-3:00 - BRT
#
# Maranhao (MA), Piaui (PI), Ceara (CE), Rio Grande do Norte (RN),
# Paraiba (PB)
Zone America/Fortaleza -2:34:00 - LMT 1914
-3:00 Brazil BR%sT 1990 Sep 17
-3:00 - BRT 1999 Sep 30
-3:00 Brazil BR%sT 2000 Oct 22
-3:00 - BRT 2001 Sep 13
-3:00 Brazil BR%sT 2002 Oct 1
-3:00 - BRT
#
# Pernambuco (PE) (except Atlantic islands)
Zone America/Recife -2:19:36 - LMT 1914
-3:00 Brazil BR%sT 1990 Sep 17
-3:00 - BRT 1999 Sep 30
-3:00 Brazil BR%sT 2000 Oct 15
-3:00 - BRT 2001 Sep 13
-3:00 Brazil BR%sT 2002 Oct 1
-3:00 - BRT
#
# Tocantins (TO)
Zone America/Araguaina -3:12:48 - LMT 1914
-3:00 Brazil BR%sT 1990 Sep 17
-3:00 - BRT 1995 Sep 14
-3:00 Brazil BR%sT 2003 Sep 24
-3:00 - BRT
#
# Alagoas (AL), Sergipe (SE)
Zone America/Maceio -2:22:52 - LMT 1914
-3:00 Brazil BR%sT 1990 Sep 17
-3:00 - BRT 1995 Oct 13
-3:00 Brazil BR%sT 1996 Sep 4
-3:00 - BRT 1999 Sep 30
-3:00 Brazil BR%sT 2000 Oct 22
-3:00 - BRT 2001 Sep 13
-3:00 Brazil BR%sT 2002 Oct 1
-3:00 - BRT
#
# Bahia (BA)
# There are too many Salvadors elsewhere, so use America/Bahia instead
# of America/Salvador.
Zone America/Bahia -2:34:04 - LMT 1914
-3:00 Brazil BR%sT 2003 Sep 24
-3:00 - BRT
#
# 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)
Zone America/Sao_Paulo -3:06:28 - LMT 1914
-3:00 Brazil BR%sT 1963 Oct 23 00:00
-3:00 1:00 BRST 1964
-3:00 Brazil BR%sT
#
# Mato Grosso do Sul (MS)
Zone America/Campo_Grande -3:38:28 - LMT 1914
-4:00 Brazil AM%sT
#
# Mato Grosso (MT)
Zone America/Cuiaba -3:44:20 - LMT 1914
-4:00 Brazil AM%sT 2003 Sep 24
-4:00 - AMT 2004 Oct 1
-4:00 Brazil AM%sT
#
# west Para (PA), Rondonia (RO)
# West Para includes Altamira, Oribidos, Prainha, Oriximina, and Santarem.
Zone America/Porto_Velho -4:15:36 - LMT 1914
-4:00 Brazil AM%sT 1988 Sep 12
-4:00 - AMT
#
# Roraima (RR)
Zone America/Boa_Vista -4:02:40 - LMT 1914
-4:00 Brazil AM%sT 1988 Sep 12
-4:00 - AMT 1999 Sep 30
-4:00 Brazil AM%sT 2000 Oct 15
-4:00 - AMT
#
# east Amazonas (AM): Boca do Acre, Jutai, Manaus, Floriano Peixoto
# The great circle line from Tabatinga to Porto Acre divides
# east from west Amazonas.
Zone America/Manaus -4:00:04 - LMT 1914
-4:00 Brazil AM%sT 1988 Sep 12
-4:00 - AMT 1993 Sep 28
-4:00 Brazil AM%sT 1994 Sep 22
-4:00 - AMT
#
# west Amazonas (AM): Atalaia do Norte, Boca do Maoco, Benjamin Constant,
# Eirunepe, Envira, Ipixuna
Zone America/Eirunepe -4:39:28 - LMT 1914
-5:00 Brazil AC%sT 1988 Sep 12
-5:00 - ACT 1993 Sep 28
-5:00 Brazil AC%sT 1994 Sep 22
-5:00 - ACT
#
# Acre (AC)
Zone America/Rio_Branco -4:31:12 - LMT 1914
-5:00 Brazil AC%sT 1988 Sep 12
-5:00 - ACT
# Chile
# 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.
# (1998-09-29):
# 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 Gwillim Law (2001-05-04):
# I came across another article in "La Tercera" about Chilean DST.
#
# It clearly confirms my earlier suggestion, that DST begins at 22:00
# on Easter Island.... But it also seems to be saying that the
# observance of DST in Chile began in 1966, rather than 1969 as
# ... [Shanks] has it....
#
# My translation:
#
# "The Chilean Army has announced that summer time will begin tomorrow,
# Saturday, October 14 in continental Chile, insular Chile, and
# Antarctica, as provided by Supreme Decree 25 of January 11, 1966.
# By the preceding, official time in continental Chile and Chilean
# Antarctic, and official time in Western Insular Chile, which applies
# to Easter Island and Sala y Gomez Island, will be set forward at
# midnight and at 22:00, respectively, by 20 minutes."
# From Paul Eggert (2001-05-04):
# Go with this article in preference to Shanks's 1969 date for modern DST.
# Assume this rule has been used since DST was introduced in the islands.
# From Paul Eggert (2002-10-24):
# gives many details that
# disagree with the following table, but we haven't had time to compare them.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Chile 1918 only - Sep 1 0:00 1:00 S
Rule Chile 1919 only - Jul 2 0:00 0 -
Rule Chile 1927 1931 - Sep 1 0:00 1:00 S
Rule Chile 1928 1932 - Apr 1 0:00 0 -
Rule Chile 1966 1997 - Oct Sun>=9 4:00u 1:00 S
Rule Chile 1967 1998 - 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 max - Oct Sun>=9 4:00u 1:00 S
Rule Chile 2000 max - Mar Sun>=9 3:00u 0 -
# IATA SSIM anomalies: (1990-09) says 1990-09-16; (1992-02) says 1992-03-14;
# (1996-09) says 1998-03-08. Ignore these.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Santiago -4:42:40 - LMT 1890
-4:42:40 - SMT 1910 # Santiago Mean Time
-5:00 Chile CL%sT 1932 Sep # Chile Time
-4:00 Chile CL%sT
Zone Pacific/Easter -7:17:28 - LMT 1890 # Mataveri
-7:17:28 - MMT 1932 Sep # Mataveri Mean Time
-7:00 Chile EAS%sT 1982 Mar 14 # Easter I Time
-6:00 Chile EAS%sT
#
# Sala y Gomez Island is like Pacific/Easter.
# Other Chilean locations, including Juan Fernandez Is, San Ambrosio,
# San Felix, and Antarctic bases, are like America/Santiago.
# Colombia
# Shanks specifies 24:00 for 1992 transition times; go with IATA,
# as it seems implausible to change clocks at midnight New Year's Eve.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule CO 1992 only - May 2 0:00 1:00 S
Rule CO 1992 only - Dec 31 0:00 0 -
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Bogota -4:56:20 - LMT 1884 Mar 13
-4:56:20 - BMT 1914 Nov 23 # Bogota Mean Time
-5:00 CO CO%sT # Colombia Time
# Malpelo, Providencia, San Andres
# no information; probably like America/Bogota
# Curacao
# Shanks says that Bottom and Oranjestad 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.
# This all predates our 1970 cutoff, though.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Curacao -4:35:44 - LMT 1912 Feb 12 # Willemstad
-4:30 - ANT 1965 # Netherlands Antilles Time
-4:00 - AST
# Ecuador
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Guayaquil -5:19:20 - LMT 1890
-5:14:00 - QMT 1931 # Quito Mean Time
-5:00 - ECT # Ecuador Time
Zone Pacific/Galapagos -5:58:24 - LMT 1931 # Puerto Baquerizo Moreno
-5:00 - ECT 1986
-6:00 - GALT # Galapagos Time
# Falklands
# From Paul Eggert (2001-03-05):
# Between 1990 and 2000 inclusive, Shanks and the IATA agree except
# the IATA gives 1996-09-08. Go with Shanks.
# From Falkland Islands Government Office, London (2001-01-22)
# via Jesper Norgaard:
# ... 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
# Sunday 1 September.
# 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
# what was said then:
#
# "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
# as UK or Chile."
#
# 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
# better info.
# 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 max - Apr Sun>=15 2:00 0 -
Rule Falk 2001 max - Sep Sun>=1 2:00 1:00 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone Atlantic/Stanley -3:51:24 - LMT 1890
-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
# French Guiana
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Cayenne -3:29:20 - LMT 1911 Jul
-4:00 - GFT 1967 Oct # French Guiana Time
-3:00 - GFT
# Guyana
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Guyana -3:52:40 - LMT 1915 Mar # Georgetown
-3:45 - GBGT 1966 May 26 # Br Guiana Time
-3:45 - GYT 1975 Jul 31 # Guyana Time
-3:00 - GYT 1991
# IATA SSIM (1996-06) says -4:00. Assume a 1991 switch.
-4:00 - GYT
# Paraguay
# From Paul Eggert (1999-10-29):
# Shanks (1999) says that spring transitions are from 01:00 -> 02:00,
# and autumn transitions are from 00:00 -> 23:00. Go with earlier
# 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
# (10-01).
#
# 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.
#
# From Jesper Norgaard (2001-03-06) [an official URL saying similar things]:
# http://gateway.abc.com.py:8000/pub/pag04.mbr/artic?FHA=2001-03-03-02.24.52.900592
#
Rule Para 1996 2001 - Oct Sun>=1 0:00 1:00 S
# IATA SSIM (1997-09) says Mar 1; go with Shanks.
Rule Para 1997 only - Feb lastSun 0:00 0 -
# Shanks says 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
# April.
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)
Rule Para 2004 max - Oct Sun>=15 0:00 1:00 S
Rule Para 2005 max - Mar Sun>=8 0:00 0 -
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Asuncion -3:50:40 - LMT 1890
-3:50:40 - AMT 1931 Oct 10 # Asuncion Mean Time
-4:00 - PYT 1972 Oct # Paraguay Time
-3:00 - PYT 1974 Apr
-4:00 Para PY%sT
# Peru
#
#
# From Evelyn C. Leeper via Mark Brader (2003-10-26):
# 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 (2003-11-02):
# Shanks doesn'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.
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]
Zone America/Lima -5:08:12 - LMT 1890
-5:08:36 - LMT 1908 Jul 28 # Lima Mean Time?
-5:00 Peru PE%sT # Peru Time
# South Georgia
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone Atlantic/South_Georgia -2:26:08 - LMT 1890 # Grytviken
-2:00 - GST # South Georgia Time
# South Sandwich Is
# uninhabited; scientific personnel have wintered
# Suriname
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Paramaribo -3:40:40 - LMT 1911
-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
-3:00 - SRT
# Trinidad and Tobago
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Port_of_Spain -4:06:04 - LMT 1912 Mar 2
-4:00 - AST
# Uruguay
# From Paul Eggert (1993-11-18):
# Uruguay wins the prize for the strangest peacetime manipulation of the rules.
# From Shanks:
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
# Whitman gives 1923 Oct 1; go with Shanks.
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 gives 1935 Apr 1 0:00 and 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.
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.
Rule Uruguay 1941 only - Aug 1 0:00 0 -
Rule Uruguay 1942 only - Jan 1 0:00 0:30 HS
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 says 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....
# http://www.presidencia.gub.uy/decretos/2004091502.htm
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....
# http://www.presidencia.gub.uy/_Web/noticias/2005/03/2005031005.htm
Rule Uruguay 2005 only - Mar 27 2:00 0 -
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Montevideo -3:44:44 - LMT 1898 Jun 28
-3:44:44 - MMT 1920 May 1 # Montevideo MT
-3:30 Uruguay UY%sT 1942 Dec 14 # Uruguay Time
-3:00 Uruguay UY%sT
# Venezuela
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Caracas -4:27:44 - LMT 1890
-4:27:40 - CMT 1912 Feb 12 # Caracas Mean Time?
-4:30 - VET 1965 # Venezuela Time
-4:00 - VET