From 812aff32b32c02266361d5538351e0db2a1aee5b Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Sun, 18 Aug 2024 19:09:03 -0700 Subject: [PROPOSED] Improve historical transitions in Mexico 1921-1997 (Thanks to Heitor David Pinto.) * northamerica (Mexico): 1931 DST transition was 04-30 00:00, not 05-01 23:00. (America/Cancun, America/Merida): 1981 transtion was 12-26 2:00, not 12-23. (America/Cancun): Add 1983-01-04 00:00 transition to -06 with Mexican DST, and 1997-10-26 02:00 transition to -05 with Mexican DST. (America/Merida): 1982 fall transition was 11-02 02:00, not 12-02. (America/Monterrey): The 1922 transition was to -07, not -06. Add 1927-06-10 transition to -06 and 1930-11-15 transition to -07 with Mexican DST, and 1932-04-01 transition to -06. (America/Mexico_City, America/Ciudad_Juarez, America/Ojinaga) (America/Chihuahua, America/Hermosillo, America/Mazatlan) (America/Bahia_Banderas, America/Tijuana): The 1927-06-10 transition time was unknown (defaulting to 00:00), not 23:00. (America/Hermosillo, America/Mazatlan, America/Bahia_Banderas): These locations stayed at -07 from 1949 through 1996. They did not go to -08. (America/Tijuana): The 1945 fall transition was 11-15, not 11-12. Los Angeles style DST was observed 1950 through 1952, though with minor differences in dates or hours. --- NEWS | 11 ++++- northamerica | 121 +++++++++++++++++++++++++++++++++++++++++++-------- 2 files changed, 112 insertions(+), 20 deletions(-) diff --git a/NEWS b/NEWS index abccbd20..cfc0eaee 100644 --- a/NEWS +++ b/NEWS @@ -3,7 +3,7 @@ News for the tz database Unreleased, experimental changes Briefly: - Improve historical data for Mongolia, Portugal and possessions. + Improve historical data for Mexico, Mongolia, and Portugal. System V names are now obsolescent. The main data form now uses %z. The code now conforms to RFC 8536 for early timestamps. @@ -18,6 +18,15 @@ Unreleased, experimental changes This seems better given our wildly conflicting information about Mongolia's time zone history. (Thanks to Heitor David Pinto.) + Historical transitions for Mexico have been updated based on + official Mexican decrees. The affected timestamps occur during + the years 1921-1927, 1931, 1945, 1949-1970, and 1981-1997. + The affected zones are America/Bahia_Banderas, America/Cancun, + America/Chihuahua, America/Ciudad_Juarez, America/Hermosillo, + America/Mazatlan, America/Merida, America/Mexico_City, + America/Monterrey, America/Ojinaga, and America/Tijuana. + (Thanks to Heitor David Pinto.) + Historical transitions for Portugal, represented by Europe/Lisbon, Atlantic/Azores, and Atlantic/Madeira, have been updated based on a close reading of old Portuguese legislation, replacing previous data diff --git a/northamerica b/northamerica index 74b8efc4..01f392e0 100644 --- a/northamerica +++ b/northamerica @@ -2353,6 +2353,81 @@ Zone America/Dawson -9:17:40 - LMT 1900 Aug 20 # the researchers who prepared the Decrees page failed to find some of # the relevant documents. +# From Heitor David Pinto (2024-08-04): +# In 1931, the decree implementing DST specified that it would take +# effect on 30 April.... +# https://www.dof.gob.mx/nota_to_imagen_fs.php?cod_diario=192270&pagina=2&seccion=1 +# +# In 1981, the decree changing Campeche, Yucatán and Quintana Roo to UTC-5 +# specified that it would enter into force on 26 December 1981 at 2:00.... +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4705667&fecha=23/12/1981&cod_diario=202796 +# +# In 1982, the decree returning Campeche and Yucatán to UTC-6 specified that +# it would enter into force on 2 November 1982 at 2:00.... +# https://www.dof.gob.mx/nota_to_imagen_fs.php?cod_diario=205689&pagina=3&seccion=0 +# +# Quintana Roo changed to UTC-6 on 4 January 1983 at 0:00, and again +# to UTC-5 on 26 October 1997 at 2:00.... +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4787355&fecha=28/12/1982&cod_diario=206112 +# https://www.dof.gob.mx/nota_to_imagen_fs.php?cod_diario=209559&pagina=15&seccion=0 +# +# Durango, Coahuila, Nuevo León and Tamaulipas were set to UTC-7 on 1 January +# 1922, and changed to UTC-6 on 10 June 1927. Then Durango, Coahuila and +# Nuevo León (but not Tamaulipas) returned to UTC-7 on 15 November 1930, +# observed DST in 1931, and changed again to UTC-6 on 1 April 1932.... +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4441846&fecha=29/12/1921&cod_diario=187468 +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4541520&fecha=09/06/1927&cod_diario=193920 +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4491963&fecha=15/11/1930&cod_diario=190835 +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4418437&fecha=21/01/1932&cod_diario=185588 +# +# ... the ... 10 June 1927 ... decree only said 10 June 1927, without +# specifying a time, so I suppose that it should be considered at 0:00. +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4541520&fecha=09/06/1927&cod_diario=193920 +# +# In 1942, the decree changing Baja California, Baja California Sur, Sonora, +# Sinaloa and Nayarit to UTC-7 was published on 24 April, but it said that it +# would apply from 1 April, so it's unclear when the change actually +# occurred. The database currently shows 24 April 1942. +# https://www.dof.gob.mx/nota_to_imagen_fs.php?cod_diario=192203&pagina=2&seccion=1 +# +# Baja California Sur, Sonora, Sinaloa and Nayarit never used UTC-8. The ... +# 14 January 1949 ... change [to UTC-8] only occurred in Baja California. +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4515613&fecha=13/01/1949&cod_diario=192309 +# +# In 1945, the decree changing Baja California to UTC-8 specified that it +# would take effect on the third day from its publication. +# It was published on 12 November, so it would take effect on 15 November.... +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4555049&fecha=12/11/1945&cod_diario=194763 +# +# In 1948, the decree changing Baja California to UTC-7 specified that it +# would take effect on "this date". The decree was made on 13 March, +# but published on 5 April, so it's unclear when the change actually occurred. +# The database currently shows 5 April 1948. +# https://www.dof.gob.mx/nota_to_imagen_fs.php?cod_diario=188624&pagina=2&seccion=0 +# +# In 1949, the decree changing Baja California to UTC-8 was published on 13 +# January, but it said that it would apply from 1 January, so it's unclear when +# the change actually occurred. The database currently shows 14 January 1949. +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4515613&fecha=13/01/1949&cod_diario=192309 +# +# Baja California also observed UTC-7 from 1 May to 24 September 1950, +# from 29 April to 30 September 1951 at 2:00, +# and from 27 April to 28 September 1952 at 2:00.... +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4600403&fecha=29/04/1950&cod_diario=197505 +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4623553&fecha=23/09/1950&cod_diario=198805 +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4469444&fecha=27/04/1951&cod_diario=189317 +# https://www.dof.gob.mx/nota_to_imagen_fs.php?codnota=4533868&fecha=10/03/1952&cod_diario=193465 +# +# All changes in Baja California from 1948 to 1952 match those in California, +# on the same dates or with a difference of one day. +# So it may be easier to implement these changes as DST with rule CA +# during this whole period. +# +# From Paul Eggert (2024-08-18): +# For now, maintain the slightly-different history for Baja California, +# as we have no information on whether 1948/1952 clocks in Tijuana followed +# the decrees or followed San Diego. + # From Alan Perry (1996-02-15): # A guy from our Mexico subsidiary finally found the Presidential Decree # outlining the timezone changes in Mexico. @@ -2556,7 +2631,7 @@ Zone America/Dawson -9:17:40 - LMT 1900 Aug 20 # http://puentelibre.mx/noticia/ciudad_juarez_cambio_horario_noviembre_2022/ # Rule NAME FROM TO - IN ON AT SAVE LETTER/S -Rule Mexico 1931 only - May 1 23:00 1:00 D +Rule Mexico 1931 only - April 30 0:00 1:00 D Rule Mexico 1931 only - Oct 1 0:00 0 S Rule Mexico 1939 only - Feb 5 0:00 1:00 D Rule Mexico 1939 only - Jun 25 0:00 0 S @@ -2575,14 +2650,16 @@ Rule Mexico 2002 2022 - Oct lastSun 2:00 0 S # Zone NAME STDOFF RULES FORMAT [UNTIL] # Quintana Roo; represented by Cancún Zone America/Cancun -5:47:04 - LMT 1922 Jan 1 6:00u - -6:00 - CST 1981 Dec 23 + -6:00 - CST 1981 Dec 26 2:00 + -5:00 - EST 1983 Jan 4 0:00 + -6:00 Mexico C%sT 1997 Oct 26 2:00 -5:00 Mexico E%sT 1998 Aug 2 2:00 -6:00 Mexico C%sT 2015 Feb 1 2:00 -5:00 - EST # Campeche, Yucatán; represented by Mérida Zone America/Merida -5:58:28 - LMT 1922 Jan 1 6:00u - -6:00 - CST 1981 Dec 23 - -5:00 - EST 1982 Dec 2 + -6:00 - CST 1981 Dec 26 2:00 + -5:00 - EST 1982 Nov 2 2:00 -6:00 Mexico C%sT # Coahuila, Nuevo León, Tamaulipas (near US border) # This includes the following municipios: @@ -2599,12 +2676,15 @@ Zone America/Matamoros -6:30:00 - LMT 1922 Jan 1 6:00u -6:00 US C%sT # Durango; Coahuila, Nuevo León, Tamaulipas (away from US border) Zone America/Monterrey -6:41:16 - LMT 1922 Jan 1 6:00u + -7:00 - MST 1927 Jun 10 + -6:00 - CST 1930 Nov 15 + -7:00 Mexico M%sT 1932 Apr 1 -6:00 - CST 1988 -6:00 US C%sT 1989 -6:00 Mexico C%sT # Central Mexico Zone America/Mexico_City -6:36:36 - LMT 1922 Jan 1 7:00u - -7:00 - MST 1927 Jun 10 23:00 + -7:00 - MST 1927 Jun 10 -6:00 - CST 1930 Nov 15 -7:00 Mexico M%sT 1932 Apr 1 -6:00 Mexico C%sT 2001 Sep 30 2:00 @@ -2615,7 +2695,7 @@ Zone America/Mexico_City -6:36:36 - LMT 1922 Jan 1 7:00u # Práxedis G Guerrero. # http://gaceta.diputados.gob.mx/PDF/65/2a022/nov/20221124-VII.pdf Zone America/Ciudad_Juarez -7:05:56 - LMT 1922 Jan 1 7:00u - -7:00 - MST 1927 Jun 10 23:00 + -7:00 - MST 1927 Jun 10 -6:00 - CST 1930 Nov 15 -7:00 Mexico M%sT 1932 Apr 1 -6:00 - CST 1996 @@ -2630,7 +2710,7 @@ Zone America/Ciudad_Juarez -7:05:56 - LMT 1922 Jan 1 7:00u # Benavides. # http://gaceta.diputados.gob.mx/PDF/65/2a022/nov/20221124-VII.pdf Zone America/Ojinaga -6:57:40 - LMT 1922 Jan 1 7:00u - -7:00 - MST 1927 Jun 10 23:00 + -7:00 - MST 1927 Jun 10 -6:00 - CST 1930 Nov 15 -7:00 Mexico M%sT 1932 Apr 1 -6:00 - CST 1996 @@ -2642,7 +2722,7 @@ Zone America/Ojinaga -6:57:40 - LMT 1922 Jan 1 7:00u -6:00 US C%sT # Chihuahua (away from US border) Zone America/Chihuahua -7:04:20 - LMT 1922 Jan 1 7:00u - -7:00 - MST 1927 Jun 10 23:00 + -7:00 - MST 1927 Jun 10 -6:00 - CST 1930 Nov 15 -7:00 Mexico M%sT 1932 Apr 1 -6:00 - CST 1996 @@ -2652,23 +2732,21 @@ Zone America/Chihuahua -7:04:20 - LMT 1922 Jan 1 7:00u -6:00 - CST # Sonora Zone America/Hermosillo -7:23:52 - LMT 1922 Jan 1 7:00u - -7:00 - MST 1927 Jun 10 23:00 + -7:00 - MST 1927 Jun 10 -6:00 - CST 1930 Nov 15 -7:00 Mexico M%sT 1932 Apr 1 -6:00 - CST 1942 Apr 24 - -7:00 - MST 1949 Jan 14 - -8:00 - PST 1970 + -7:00 - MST 1996 -7:00 Mexico M%sT 1999 -7:00 - MST # Baja California Sur, Nayarit (except Bahía de Banderas), Sinaloa Zone America/Mazatlan -7:05:40 - LMT 1922 Jan 1 7:00u - -7:00 - MST 1927 Jun 10 23:00 + -7:00 - MST 1927 Jun 10 -6:00 - CST 1930 Nov 15 -7:00 Mexico M%sT 1932 Apr 1 -6:00 - CST 1942 Apr 24 - -7:00 - MST 1949 Jan 14 - -8:00 - PST 1970 + -7:00 - MST 1970 -7:00 Mexico M%sT # Bahía de Banderas @@ -2701,27 +2779,32 @@ Zone America/Mazatlan -7:05:40 - LMT 1922 Jan 1 7:00u # Use "Bahia_Banderas" to keep the name to fourteen characters. Zone America/Bahia_Banderas -7:01:00 - LMT 1922 Jan 1 7:00u - -7:00 - MST 1927 Jun 10 23:00 + -7:00 - MST 1927 Jun 10 -6:00 - CST 1930 Nov 15 -7:00 Mexico M%sT 1932 Apr 1 -6:00 - CST 1942 Apr 24 - -7:00 - MST 1949 Jan 14 - -8:00 - PST 1970 + -7:00 - MST 1970 -7:00 Mexico M%sT 2010 Apr 4 2:00 -6:00 Mexico C%sT # Baja California Zone America/Tijuana -7:48:04 - LMT 1922 Jan 1 7:00u -7:00 - MST 1924 - -8:00 - PST 1927 Jun 10 23:00 + -8:00 - PST 1927 Jun 10 -7:00 - MST 1930 Nov 15 -8:00 - PST 1931 Apr 1 -8:00 1:00 PDT 1931 Sep 30 -8:00 - PST 1942 Apr 24 -8:00 1:00 PWT 1945 Aug 14 23:00u - -8:00 1:00 PPT 1945 Nov 12 # Peace + -8:00 1:00 PPT 1945 Nov 15 # Peace -8:00 - PST 1948 Apr 5 -8:00 1:00 PDT 1949 Jan 14 + -8:00 - PST 1950 May 1 + -8:00 1:00 PDT 1950 Sep 24 + -8:00 - PST 1951 Apr 29 2:00 + -8:00 1:00 PDT 1951 Sep 30 2:00 + -8:00 - PST 1952 Apr 27 2:00 + -8:00 1:00 PDT 1952 Sep 28 2:00 -8:00 - PST 1954 -8:00 CA P%sT 1961 -8:00 - PST 1976 -- 2.43.0