freebsd-skq/share/zoneinfo/southamerica
1997-10-25 18:27:25 +00:00

552 lines
20 KiB
Plaintext

# @(#)southamerica 7.18
# 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 <eggert@twinsun.com> (1996-11-22):
# A good source for time zone historical data outside the U.S. is
# Thomas G. Shanks, The International Atlas (3rd edition),
# San Diego: ACS Publications, Inc. (1991).
#
# Gwillim Law <LAW@encmail.encompass.com> 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.
#
# The following abbreviations are used in this file.
# Corrections are welcome!
# std dst
# LMT Local Mean Time
# -2:00 FST FDT Fernando de Noronha
# -3:00 EST EDT Eastern Brazil
# -4:00 WST WDT Western Brazil
# -4:00 AST ADT Atlantic
# -5:00 AST ADT Acre
#
# See the `africa' file for time zone naming and abbreviation conventions.
# 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
# From Guy Harris:
# From Official Airline Guide - Worldwide Edition (1987). Countries not
# listed here do not observe DST, according to the OAG. Time zone names
# are pure inventions, and none are supplied for countries not observing
# DST; updates from natives would be appreciated. The times that DST
# starts and ends are based on the assumption that they switch a 2AM just
# as everybody else does.
###############################################################################
###############################################################################
# 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 <hernan@isoft.com.ar> (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 1 0:00 0 -
Rule Arg 1967 1968 - Oct Sun<=7 0:00 1:00 S
Rule Arg 1968 1969 - Apr Sun<=7 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 1974 1976 - Oct Sun<=7 0:00 1:00 S
Rule Arg 1975 1977 - Apr Sun<=7 0:00 0 -
Rule Arg 1985 only - Nov 2 0:00 1:00 S
Rule Arg 1986 only - Mar 14 0:00 0 -
Rule Arg 1986 1987 - Oct 25 0:00 1:00 S
Rule Arg 1987 only - Feb 13 0:00 0 -
Rule Arg 1988 only - Feb 7 0:00 0 -
Rule Arg 1988 only - Dec 1 0:00 1:00 S
#
# From Hernan G. Otero <hernan@isoft.com.ar> (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 gives 1989 Mar 16 and stops after 1990 Mar 4; 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 <hernan@isoft.com.ar> (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.
#
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
#
# Buenos Aires (BA), Distrito Federal (DF), Santa Cruz (SC),
# Tierra del Fuego (TF) & Antartida e Islas
Zone America/Buenos_Aires -3:53:48 - LMT 1894 Nov
-4:16:44 - CMT 1920 May # Cordoba Mean Time
-4:00 - ART 1930 Dec
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT
#
# Santa Fe (SF), Entre Rios (ER), Corrientes (CN), Misiones (MN), Chaco (CC),
# Formosa (FM), La Pampa (LP), Chubut (CH)
Zone America/Rosario -4:02:40 - LMT 1894 Nov
-4:16:44 - CMT 1920 May
-4:00 - ART 1930 Dec
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1991 Jul
-3:00 - ART
#
# Cordoba (CB), Santiago del Estero (SE), Salta (SA), Tucuman (TM), La Rioja (LR), San Juan (SJ), San Luis (SL),
# Neuquen (NQ), Rio Negro (RN)
Zone America/Cordoba -4:16:44 - LMT 1894 Nov
-4:16:44 - CMT 1920 May
-4:00 - ART 1930 Dec
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1990 Jul
-3:00 - ART
#
# Jujuy (JY)
Zone America/Jujuy -4:21:12 - LMT 1894 Nov
-4:16:44 - 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 6
-4:00 1:00 WARST 1992 Mar 15
-4:00 - WART 1992 Oct 18
-3:00 - ART
#
# Catamarca (CT)
Zone America/Catamarca -4:23:08 - LMT 1894 Nov
-4:16:44 - CMT 1920 May
-4:00 - ART 1930 Dec
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1990 Jul
-3:00 - ART 1991 Jul
-3:00 Arg AR%sT 1992 Jul
-3:00 - ART
#
# Mendoza (MZ)
Zone America/Mendoza -4:35:16 - LMT 1894 Nov
-4:16:44 - 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 15
-4:00 1:00 WARST 1992 Mar 1
-4:00 - WART 1992 Oct 18
-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 - LPMT 1931 Oct 15 # La Paz Mean Time
-4:32:36 1:00 BOST 1932 Mar 21 # Bolivia ST
-4:00 - BOT # Bolivia Time
# Brazil
# From Guy Harris:
# The OAG lists 1987-10-25 and 1988-02-12 as the starting and
# ending dates, giving them as "estimated date(s) based on previous year". We
# infer a rule here from one example, always a dangerous practice.... Yes,
# they really do switch on Saturday, according to the OAG.
# "[America/Porto_Acre]" is for the Territory of Acre;
# "[America/Noronha]" is for Fernando De Noronha.
# From Paul Eggert <eggert@twinsun.com> (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 Paul Eggert (1996-11-22):
# Let's make the following assumptions:
#
# * All data in Shanks are correct through 1990. In particular,
# Shanks was right when he said Acre stopped observing DST in mid-1988.
# * Areas where Shanks reports DST up to 1990, but the IATA reports no DST
# in 1995, stopped observing DST in mid-1990.
#
# Under these assumptions Brazil needs 7 entries to cover all the distinct
# time zone histories since 1970:
#
# Noronha (UTC-2), Fortaleza (UTC-3), and Manaus (UTC-4) stopped observing DST
# in mid-1990.
# Maceio (UTC-3) stopped observing DST in mid-1990, but started again mid-1995.
# Sao Paulo (UTC-3) and Cuiaba (UTC-4) always observed DST.
# Porto Acre (UTC-5) stopped observing DST in mid-1988.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Brazil 1931 only - Oct 3 11:00 1:00 D
Rule Brazil 1932 1933 - Apr 1 0:00 0 S
Rule Brazil 1932 only - Oct 3 0:00 1:00 D
Rule Brazil 1949 1952 - Dec 1 0:00 1:00 D
Rule Brazil 1950 only - Apr 16 0:00 0 S
Rule Brazil 1951 1953 - Apr 1 0:00 0 S
Rule Brazil 1963 only - Dec 9 0:00 1:00 D
Rule Brazil 1964 only - Mar 1 0:00 0 S
Rule Brazil 1965 only - Jan 31 0:00 1:00 D
Rule Brazil 1965 only - Apr 1 0:00 0 S
Rule Brazil 1965 only - Dec 1 0:00 1:00 D
Rule Brazil 1966 1968 - Mar 1 0:00 0 S
Rule Brazil 1966 1967 - Nov 1 0:00 1:00 D
Rule Brazil 1985 only - Nov 2 0:00 1:00 D
Rule Brazil 1986 only - Mar 15 0:00 0 S
Rule Brazil 1986 1987 - Oct Sat<=28 0:00 1:00 D
Rule Brazil 1987 only - Feb 14 0:00 0 S
Rule Brazil 1988 only - Feb 7 0:00 0 S
Rule Brazil 1989 only - Jan 22 0:00 0 S
Rule Brazil 1988 1989 - Oct Sun>=10 0:00 1:00 D
Rule Brazil 1990 1991 - Feb Sun>=11 0:00 0 S
Rule Brazil 1990 1992 - Oct Sun>=20 0:00 1:00 D
Rule Brazil 1992 only - Feb 9 0:00 0 S
Rule Brazil 1993 1995 - Oct Sun>=11 0:00 1:00 D
Rule Brazil 1993 only - Jan 31 0:00 0 S
Rule Brazil 1994 1995 - Feb Sun>=15 0:00 0 S
Rule Brazil 1996 max - Feb Sun>=11 0:00 0 S
Rule Brazil 1996 max - Oct Sun>=1 0:00 1:00 D
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
#
# Fernando de Noronha
Zone America/Noronha -2:09:40 - LMT 1914
-2:00 - FST 1963 Dec 9
-2:00 Brazil F%sT 1990 Jul
-2:00 - FST
#
# Amapa, east Para, Maranhao, Piaui, Ceara, Rio Grande do Norte, Paraiba,
# Pernambuco (except Fernando de Noronha)
Zone America/Fortaleza -2:34:00 - LMT 1914
-3:00 - EST 1963 Dec 9
-3:00 Brazil E%sT 1990 Jul
-3:00 - EST
#
# Alagoas, Sergipe, Tocantins
Zone America/Maceio -2:22:52 - LMT 1914
-3:00 - EST 1963 Dec 9
-3:00 Brazil E%sT 1990 Jul
-3:00 - EST 1995 Jul
-3:00 Brazil E%sT
#
# Bahia, Goias, Distrito Federal, Minas Gerais, Espirito Santo, Rio de Janeiro,
# Sao Paulo, Parana, Santa Catarina, Rio Grande do Sul
Zone America/Sao_Paulo -3:06:28 - LMT 1914
-3:00 Brazil E%sT
#
# Mato Grosso, Mato Grosso do Sul
Zone America/Cuiaba -3:44:20 - LMT 1914
-4:00 - WST 1963 Dec 9
-4:00 Brazil W%sT
#
# Roraima, west Para, Amazonas, Rondonia
Zone America/Manaus -4:00:04 - LMT 1914
-4:00 - WST 1963 Dec 9
-4:00 Brazil W%sT 1990 Jul
-4:00 - WST
#
# Acre
# Rio_Branco is too ambiguous, since there's a Rio Branco in Uruguay too.
Zone America/Porto_Acre -4:31:12 - LMT 1914
-5:00 - AST 1963 Dec 9
-5:00 Brazil A%sT 1988 Jul
-5:00 - AST
#
# Martin Vaz and Trinidade are like America/Noronha.
# 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.
# 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 1969 max - Oct Sun>=9 0:00 1:00 S
Rule Chile 1970 max - Mar Sun>=9 0:00 0 -
# IATA SSIM anomalies: (1990-09) says 1990-09-16; (1992-02) says 1992-03-14;
# (1996-09) says 1998-03-08. Ignore these for now.
# 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
#
# Whitman says Juan Fernandez Is are like America/Santiago.
# San Ambrosio, San Felix
# no information; probably like America/Santiago
# Colombia
# 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
# 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
# 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 1995 - Sep Sun>=9 0:00 1:00 S
Rule Falk 1986 max - Apr Sun>=16 0:00 0 -
Rule Falk 1996 max - Sep Sun>=8 0:00 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 Bob Devine (1988-01-28):
# Paraguay: First day in October to last in March. Midnight switch??
# Since 1980.
# From U. S. Naval Observatory (1989-01-19):
# PARAGUAY 4 H BEHIND UTC
# PARAGUAY 3 H BEHIND UTC OCT 1, '88-MAR 31, '89
# From Shanks (1991):
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Para 1975 1978 - Oct 1 0:00 1:00 S
Rule Para 1975 1978 - Mar 1 0:00 0 -
# Shanks says 1979 was all DST.
Rule Para 1980 1991 - Apr 1 0:00 0 -
Rule Para 1980 1988 - Oct 1 0:00 1:00 S
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 max - Mar 1 0:00 0 -
Rule Para 1996 only - Oct 6 0:00 1:00 S
Rule Para 1997 max - Oct 1 0:00 1:00 S
# 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
# 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 1987 only - Jan 1 0:00 1:00 S
Rule Peru 1987 only - 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 -
Rule Peru 1993 only - Jan 1 0:00 1:00 S
Rule Peru 1993 only - Apr 1 0:00 0 -
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Lima -5:08:12 - LMT 1890
-5:09 - 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
# 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 <eggert@twinsun.com> (1993-11-18):
# Uruguay wins the prize for the strangest peacetime manipulation of the rules.
# From Shanks (1991):
# 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
Rule Uruguay 1990 1992 - Mar Sun>=1 0:00 0 -
Rule Uruguay 1990 1991 - Oct Sun>=21 0:00 1:00 S
# Shanks's 4th edition (1995) 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 1992 only - Oct 18 0:00 1:00 S
Rule Uruguay 1993 only - Feb 28 0:00 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
-4:27:44 - CMT 1912 Feb 12 # Caracas Mean Time
-4:30 - VET 1965 # Venezuela Time
-4:00 - VET