3 # This data is by no means authoritative; if you think you know better,
4 # go ahead and edit the file (and please send any changes to
5 # tz@elsie.nci.nih.gov for general use in the future).
7 # From Paul Eggert <eggert@twinsun.com> (November 18, 1993):
8 # A good source for time zone historical data outside the U.S. is
9 # Thomas G. Shanks, The International Atlas (3rd edition),
10 # San Diego: ACS Publications, Inc. (1991).
11 # Except where otherwise noted, it is the source for the data below.
13 # I invented the abbreviations marked `*' in the following table;
14 # the rest are from earlier versions of this file, or from other sources.
15 # Some of these are just plausible excuses for common English abbreviations.
16 # Corrections are welcome!
19 # -2:00 FST FDT Fernando de Noronha
20 # -3:00 EST EDT Eastern South America (conflicts with -5:00)
21 # -3:00 ARST ARDT Argentina
22 # -4:00 AST ADT Andes*, Antilles*, Asuncion*, Atlantic
23 # -4:00 CST CDT Chile (conflicts with -6:00)
24 # -4:00 WST WDT Western Brazil
25 # -5:00 AST ADT Acre (conflicts with -4:00)
26 # -5:00 EST EDT Eastern, Ecuador*
27 # -6:00 CST CDT Archipelago of Columbus*, Central
28 # -7:00 MST MDT Mataveri*, Mountain
30 # See the `africa' file for Zone naming conventions.
33 # From Official Airline Guide - Worldwide Edition (1987). Countries not
34 # listed here do not observe DST, according to the OAG. Time zone names
35 # are pure inventions, and none are supplied for countries not observing
36 # DST; updates from natives would be appreciated. The times that DST
37 # starts and ends are based on the assumption that they switch a 2AM just
38 # as everybody else does.
40 ###############################################################################
42 ###############################################################################
46 # From Bob Devine (January 28, 1988):
47 # Argentina: first Sunday in October to first Sunday in April since 1976.
48 # Double Summer time from 1969 to 1974. Switches at midnight.
50 # From U. S. Naval Observatory (January 19, 19889):
51 # ARGENTINA 3 H BEHIND UTC
53 # From Hernan G. Otero <hernan@isoft.com.ar> (June 26, 1995):
54 # I am sending modifications to the Argentinian time zone table...
55 # AR was chosen because they are the ISO letters that represent Argentina.
57 # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
58 Rule Arg 1930 only - Dec 1 0:00 1:00 D
59 Rule Arg 1931 only - Apr 1 0:00 0 S
60 Rule Arg 1931 only - Oct 15 0:00 1:00 D
61 Rule Arg 1932 1940 - Mar 1 0:00 0 S
62 Rule Arg 1932 1939 - Nov 1 0:00 1:00 D
63 Rule Arg 1940 only - Jul 1 0:00 1:00 D
64 Rule Arg 1941 only - Jun 15 0:00 0 S
65 Rule Arg 1941 only - Oct 15 0:00 1:00 D
66 Rule Arg 1943 only - Aug 1 0:00 0 S
67 Rule Arg 1943 only - Oct 15 0:00 1:00 D
68 Rule Arg 1946 only - Mar 1 0:00 0 S
69 Rule Arg 1946 only - Oct 1 0:00 1:00 D
70 Rule Arg 1963 only - Oct 1 0:00 0 S
71 Rule Arg 1963 only - Dec 15 0:00 1:00 D
72 Rule Arg 1964 1966 - Mar 1 0:00 0 S
73 Rule Arg 1964 1966 - Oct 15 0:00 1:00 D
74 Rule Arg 1967 only - Apr 1 0:00 0 S
75 Rule Arg 1967 1968 - Oct Sun<=7 0:00 1:00 D
76 Rule Arg 1968 1969 - Apr Sun<=7 0:00 0 S
77 Rule Arg 1974 only - Jan 23 0:00 1:00 D
78 Rule Arg 1974 only - May 1 0:00 0 S
79 Rule Arg 1974 1976 - Oct Sun<=7 0:00 1:00 D
80 Rule Arg 1975 1977 - Apr Sun<=7 0:00 0 S
81 Rule Arg 1985 only - Nov 2 0:00 1:00 D
82 Rule Arg 1986 only - Mar 14 0:00 0 S
83 Rule Arg 1986 1987 - Oct 25 0:00 1:00 D
84 Rule Arg 1987 only - Feb 13 0:00 0 S
85 Rule Arg 1988 only - Feb 7 0:00 0 S
86 Rule Arg 1988 only - Dec 1 0:00 1:00 D
88 # From Hernan G. Otero <hernan@isoft.com.ar> (June 26, 1995):
89 # These corrections were contributed by InterSoft Argentina S.A.,
90 # obtaining the data from the:
91 # Talleres de Hidrografia Naval Argentina
92 # (Argentinian Naval Hydrography Institute)
94 # Shanks gives 1989 Mar 16 and stops after 1990 Mar 4; go with Otero.
95 Rule Arg 1989 1993 - Mar Sun>=1 0:00 0 S
96 Rule Arg 1989 1992 - Oct Sun>=15 0:00 1:00 D
98 # From Hernan G. Otero <hernan@isoft.com.ar> (June 26, 1995):
99 # From this moment on, the law that mandated the daylight saving
100 # time corrections was derogated and no more modifications
101 # to the time zones (for daylight saving) are now made.
103 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
104 Zone America/Buenos_Aires -3:53:48 - LMT 1894 Nov
105 -4:17 - CMT 1920 May # Cordoba Mean Time
107 -4:00 Arg A%sT 1969 Oct 5
111 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
112 Zone America/La_Paz -4:32:36 - LMT 1890
113 -4:33 - LPMT 1931 Oct 15 # La Paz Mean Time
114 -4:33 1:00 LPDT 1932 Mar 21
120 # The OAG lists October 25, 1987 and February 12, 1988 as the starting and
121 # ending dates, giving them as "estimated date(s) based on previous year". We
122 # infer a rule here from one example, always a dangerous practice.... Yes,
123 # they really do switch on Saturday, according to the OAG.
124 # "Brazil/Acre" is for the Territory of Acre; "Brazil/DeNoronha" is for
125 # Fernando De Noronha.
127 # From Bob Devine (January 28, 1988):
128 # The only information I found is that there was no DST up to 1985.
129 # But there was some before 1952!
131 # From U. S. Naval Observatory (January 16, 1989):
132 # BRAZIL WEST 5 H BEHIND UTC TERRITORY OF ACRE
133 # BRAZIL WEST 4 H BEHIND UTC ACRE OCT 23, '88-FEB 11,
134 # BRAZIL '89 (ESTIMATED)
135 # BRAZIL CENTRAL 4 H BEHIND UTC MANAUS
136 # BRAZIL CENTRAL 3 H BEHIND UTC MANAUS OCT 23, '88-FEB 11,
137 # BRAZIL CENTRAL '89 (ESTIMATED)
138 # BRAZIL EAST 3 H BEHIND UTC COASTAL STATES, RIO, SAO
139 # BRAZIL EAST PAULO, BRASILIA
140 # BRAZIL EAST 2 H BEHIND UTC COASTAL STATES, RIO, SAO
141 # BRAZIL PAULO, BRASILIA OCT 23,
142 # BRAZIL '88-FEB 11, '89
144 # BRAZIL 2 H BEHIND UTC ATLANTIC ISLANDS, FERNANDO
146 # BRAZIL 1 H BEHIND UTC OCT 23, '88-FEB 11, '89
148 # BRAZIL 3 H BEHIND UTC FOR MOST MAJOR AIRPORTS.
150 # From Paul Eggert <eggert@twinsun.com> (November 18, 1993):
151 # The mayor of Rio recently attempted to change the time zone rules
152 # just in his city, in order to leave more summer time for the tourist trade.
153 # The rule change lasted only part of the day;
154 # the federal government refused to follow the city's rules, and business
155 # was in a chaos, so the mayor backed down that afternoon.
156 # Shanks claims Acre stopped observing DST after 1988 Feb 7, but it
157 # could just be that his table ran out of room. We're extrapolating
158 # about time zone changes after 1990 Feb 11.
160 # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
161 Rule Brazil 1914 only - Jan 1 0:00 0 S
162 Rule Brazil 1931 only - Oct 3 11:00 1 D
163 Rule Brazil 1932 1933 - Apr 1 0:00 0 S
164 Rule Brazil 1932 only - Oct 3 0:00 1 D
165 Rule Brazil 1949 1952 - Dec 1 0:00 1 D
166 Rule Brazil 1950 only - Apr 16 0:00 0 S
167 Rule Brazil 1951 1953 - Apr 1 0:00 0 S
168 Rule Brazil 1963 only - Dec 9 0:00 1 D
169 Rule Brazil 1964 only - Mar 1 0:00 0 S
170 Rule Brazil 1965 only - Jan 31 0:00 1 D
171 Rule Brazil 1965 only - Apr 1 0:00 0 S
172 Rule Brazil 1965 only - Dec 1 0:00 1 D
173 Rule Brazil 1966 1968 - Mar 1 0:00 0 S
174 Rule Brazil 1966 1967 - Nov 1 0:00 1 D
175 Rule Brazil 1985 only - Nov 2 0:00 1 D
176 Rule Brazil 1986 only - Mar 15 0:00 0 S
177 Rule Brazil 1986 1987 - Oct Sat<=28 0:00 1 D
178 Rule Brazil 1987 only - Feb 14 0:00 0 S
179 Rule Brazil 1988 only - Feb 7 0:00 0 S
180 Rule Brazil 1989 only - Jan 22 0:00 0 S
181 Rule Brazil 1988 max - Oct Sun>=15 0:00 1 D
182 Rule Brazil 1990 max - Feb Sun>=8 0:00 0 S
183 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
184 Zone America/Noronha -2:09:40 - LMT 1914
185 -2:00 - FST 1963 Dec 9
187 Zone America/Sao_Paulo -3:06:28 - LMT 1914
189 Zone America/Manaus -4:00:04 - LMT 1914
190 -4:00 - WST 1963 Dec 9
192 # Rio_Branco is too ambiguous, since there's a Rio Branco in Uruguay too.
193 Zone America/Porto_Acre -4:31:12 - LMT 1914
194 -5:00 - AST 1963 Dec 9
197 # Martin Vaz and Trinidade are like America/Noronha.
203 # The OAG lists October 11, 1987 and March 12, 1988 as the starting and
204 # ending dates, giving them as "estimated date(s) based on previous year."
206 # From Bob Devine (January 28, 1988):
207 # Chile has had 2nd Sunday in October to 2nd Sunday in March DST since 1977.
208 # Switch is at midnight. OAG is right.
210 # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
211 Rule Chile 1918 only - Sep 1 0:00 1:00 D
212 Rule Chile 1919 only - Jul 2 0:00 0 S
213 Rule Chile 1927 1931 - Sep 1 0:00 1:00 D
214 Rule Chile 1928 1932 - Apr 1 0:00 0 S
215 Rule Chile 1969 max - Oct Sun>=8 0:00 1:00 D
216 Rule Chile 1970 max - Mar Sun>=8 0:00 0 S
217 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
218 Zone America/Santiago -4:42:40 - LMT 1890
219 -4:43 - SMT 1910 # Santiago Mean Time
220 -5:00 Chile C%sT 1932 Sep
222 Zone Pacific/Easter -7:17:28 - LMT 1890 # Mataveri
223 -7:17 - MMT 1932 Sep # Mataveri Mean Time
224 -7:00 Chile M%sT 1982 Mar 14
227 # Whitman says Juan Fernandez Is are like America/Santiago.
228 # San Ambrosio, San Felix
229 # no information; probably like America/Santiago
233 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
234 Zone America/Bogota -4:56:20 - LMT 1884 Mar 13
235 -4:56 - BMT 1914 Nov 23 # Bogota Mean Time
237 # Malpelo, Providencia, San Andres
238 # no information; probably like America/Bogota
241 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
242 Zone America/Curacao -4:35:44 - LMT 1912 Feb 12 # Willemstad
243 -4:30 - NAST 1965 # Netherlands Antilles
247 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
248 Zone America/Guayaquil -5:19:20 - LMT 1890
249 -5:14 - QMT 1931 # Quito Mean Time
251 Zone Pacific/Galapagos -5:58:24 - LMT 1931 # Puerto Baquerizo Moreno
256 # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
257 Rule Falk 1912 only - Mar 12 0:00 0 S
258 Rule Falk 1937 1938 - Sep lastSun 0:00 1:00 D
259 Rule Falk 1938 1942 - Mar Sun>=19 0:00 0 S
260 Rule Falk 1939 only - Oct 1 0:00 1:00 D
261 Rule Falk 1940 1942 - Sep lastSun 0:00 1:00 D
262 Rule Falk 1943 only - Jan 1 0:00 0 S
263 Rule Falk 1983 only - Sep lastSun 0:00 1:00 D
264 Rule Falk 1984 1985 - Apr lastSun 0:00 0 S
265 Rule Falk 1984 only - Sep 16 0:00 1:00 D
266 Rule Falk 1985 max - Sep Sun>=9 0:00 1:00 D
267 Rule Falk 1986 max - Apr Sun>=16 0:00 0 S
268 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
269 Zone Atlantic/Stanley -3:51:24 - LMT 1890
270 -3:51 - SMT 1912 Mar 12 # Stanley Mean Time
271 -4:00 Falk A%sT 1983 May
272 -3:00 Falk E%sT 1985 Sep 15
276 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
277 Zone America/Cayenne -3:29:20 - LMT 1911 Jul
282 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
283 Zone America/Guyana -3:52:40 - LMT 1915 Mar # Georgetown
284 -3:45 - BGST 1975 Jul 31 # British Guiana ST
290 # From Bob Devine (January 28, 1988):
291 # Paraguay: First day in October to last in March. Midnight switch??
294 # From U. S. Naval Observatory (January 19, 1989):
295 # PARAGUAY 4 H BEHIND UTC
296 # PARAGUAY 3 H BEHIND UTC OCT 1, '88-MAR 31, '89
298 # From Shanks (1991):
299 # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
300 Rule Para 1974 only - Apr 1 0:00 0 S
301 Rule Para 1975 1978 - Oct 1 0:00 1:00 D
302 Rule Para 1975 1978 - Mar 1 0:00 0 S
303 # Shanks says 1979 was all DST.
304 Rule Para 1980 max - Apr 1 0:00 0 S
305 Rule Para 1980 1988 - Oct 1 0:00 1:00 D
306 Rule Para 1989 only - Oct 22 0:00 1:00 D
307 Rule Para 1990 max - Oct 1 0:00 1:00 D
308 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
309 Zone America/Asuncion -3:50:40 - LMT 1890
310 -3:51 - AMT 1931 Oct 10 # Asuncion Mean Time
316 # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
317 Rule Peru 1908 only - Jul 28 0:00 0 S
318 Rule Peru 1938 only - Jan 1 0:00 1:00 D
319 Rule Peru 1938 only - Apr 1 0:00 0 S
320 Rule Peru 1938 1939 - Sep lastSun 0:00 1:00 D
321 Rule Peru 1939 1940 - Mar Sun>=24 0:00 0 S
322 Rule Peru 1987 only - Jan 1 0:00 1:00 D
323 Rule Peru 1987 only - Apr 1 0:00 0 S
324 Rule Peru 1990 only - Jan 1 0:00 1:00 D
325 Rule Peru 1990 only - Apr 1 0:00 0 S
326 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
327 Zone America/Lima -5:08:12 - LMT 1890
328 -5:09 - LMT 1908 Jul 28
332 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
333 Zone Atlantic/South_Georgia -2:26:08 - LMT 1890 # Grytviken
340 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
341 Zone America/Paramaribo -3:40:40 - LMT 1911
342 -3:40:52 - PMT 1935 # Paramaribo Mean Time
343 -3:40:36 - PMT 1945 Oct # The capital moved?
344 -3:30 - DGST 1984 Oct # Dutch Guiana Std Time
347 # Trinidad and Tobago
348 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
349 Zone America/Port_of_Spain -4:06:04 - LMT 1912 Mar 2
353 # From Paul Eggert <eggert@twinsun.com> (November 18, 1993):
354 # Uruguay wins the prize for the strangest peacetime manipulation of the rules.
355 # Your guess is as good as mine for what happened after 1989.
356 # From Shanks (1991):
357 # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
358 Rule Uruguay 1920 only - May 1 0:00 0 S
359 # Whitman gives 1923 Oct 1; go with Shanks.
360 Rule Uruguay 1923 only - Oct 2 0:00 0:30 HD
361 Rule Uruguay 1924 1926 - Apr 1 0:00 0 S
362 Rule Uruguay 1924 1925 - Oct 1 0:00 0:30 HD
363 Rule Uruguay 1933 1935 - Oct lastSun 0:00 0:30 HD
364 # Shanks gives 1935 Apr 1 0:00 and 1936 Mar 30 0:00; go with Whitman.
365 Rule Uruguay 1934 1936 - Mar Sat>=25 23:30s 0 S
366 Rule Uruguay 1936 only - Nov 1 0:00 0:30 HD
367 Rule Uruguay 1937 1941 - Mar lastSun 0:00 0 S
368 # Whitman gives 1937 Oct 3; go with Shanks.
369 Rule Uruguay 1937 1940 - Oct lastSun 0:00 0:30 HD
370 # Whitman gives 1941 Oct 24 - 1942 Mar 27, 1942 Dec 14 - 1943 Apr 13,
371 # and 1943 Apr 13 ``to present time''; go with Shanks.
372 Rule Uruguay 1941 only - Aug 1 0:00 0 S
373 Rule Uruguay 1942 only - Jan 1 0:00 0:30 HD
374 Rule Uruguay 1942 only - Dec 14 0:00 1:00 D
375 Rule Uruguay 1943 only - Mar 14 0:00 0 S
376 Rule Uruguay 1959 only - May 24 0:00 1:00 D
377 Rule Uruguay 1959 only - Nov 15 0:00 0 S
378 Rule Uruguay 1960 only - Jan 17 0:00 1:00 D
379 Rule Uruguay 1960 only - Mar 6 0:00 0 S
380 Rule Uruguay 1965 1967 - Apr Sun>=1 0:00 1:00 D
381 Rule Uruguay 1965 only - Sep 26 0:00 0 S
382 Rule Uruguay 1966 1967 - Oct 31 0:00 0 S
383 Rule Uruguay 1968 1970 - May 27 0:00 0:30 HD
384 Rule Uruguay 1968 1970 - Dec 2 0:00 0 S
385 Rule Uruguay 1972 only - Apr 24 0:00 1:00 D
386 Rule Uruguay 1972 only - Aug 15 0:00 0 S
387 Rule Uruguay 1974 only - Mar 10 0:00 0:30 HD
388 Rule Uruguay 1974 only - Dec 22 0:00 1:00 D
389 Rule Uruguay 1976 only - Oct 1 0:00 0 S
390 Rule Uruguay 1977 only - Dec 4 0:00 1:00 D
391 Rule Uruguay 1978 only - Apr 1 0:00 0 S
392 Rule Uruguay 1979 only - Oct 1 0:00 1:00 D
393 Rule Uruguay 1980 only - May 1 0:00 0 S
394 Rule Uruguay 1987 only - Dec 14 0:00 1:00 D
395 Rule Uruguay 1988 only - Mar 14 0:00 0 S
396 Rule Uruguay 1988 only - Dec 11 0:00 1:00 D
397 Rule Uruguay 1989 only - Mar 12 0:00 0 S
398 Rule Uruguay 1989 only - Oct 29 0:00 1:00 D
399 Rule Uruguay 1990 only - Mar 4 0:00 0 S
400 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
401 Zone America/Montevideo -3:44:44 - LMT 1898 Jun 28
402 -3:45 - MMT 1920 May 1 # Montevideo MT
403 -3:30 Uruguay U%sT 1942 Dec 14 # Uruguay ST
407 # Zone NAME GMTOFF RULES FORMAT [UNTIL]
408 Zone America/Caracas -4:27:44 - LMT 1890
409 -4:28 - CMT 1912 Feb 12 # Caracas Mean Time
410 -4:30 - VZT 1965 # Venezuela Time