From 8185dfc1fba1791df5936b700cdef6cc85e3e0dd Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Mon, 4 Aug 2025 09:05:30 -0700 Subject: [PROPOSED 1/2] Fix Baja California 1951, 1961/1975 * NEWS: Mention this. * northamerica (America/Tijuana): Agree with America/Los_Angeles for 1951 and 1961/1975, instead of observing standard time all year. --- NEWS | 6 ++++++ northamerica | 24 ++++++++++++++++++------ 2 files changed, 24 insertions(+), 6 deletions(-) diff --git a/NEWS b/NEWS index 779b654e..a7916e69 100644 --- a/NEWS +++ b/NEWS @@ -2,6 +2,12 @@ News for the tz database Unreleased, experimental changes + Changes to past timestamps + + Baja California agreed with California's DST rules in 1953 and in + 1961 through 1975, instead of observing standard time all year. + (Thanks to Alois Treindl.) + Changes to build procedure Files in distributed tarballs now have correct commit times. diff --git a/northamerica b/northamerica index a6bc1b24..c29ab9fd 100644 --- a/northamerica +++ b/northamerica @@ -2444,9 +2444,23 @@ Zone America/Dawson -9:17:40 - LMT 1900 Aug 20 # 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, + +# From Alois Treindl (2025-07-29): +# I did a quick newspaper archive research on https://hndm.iib.unam.mx/ +# and found that Periódico Oficial del Estado de Baja California Norte +# (1973-04-20) states clearly that DST was observed from last Sunday +# in April to last Sunday in October.... I have a few more data from the +# official bulletin for DST begin or end in Baja California 1964 1967 1969 +# 1972 1973 (already sent) 1974 1975 1976 I do not know whether it is safe to +# assume that it also applied in the years where I did not yet find proof. +# The 1974 end of DST contains a reference to an Acuerdo of 1973-dec-20 which +# I could not find.... One might assume that Baja California, which followed +# US-CA in all these other yours, did the same. +# +# From Paul Eggert (2025-08-04): +# Assume that Tijuana agreed with San Diego from 1953 through 1996, +# as this agrees with Alois Treindl's data and with Shanks. +# For now, keep the slightly-different 1948/1952 history for Baja California, # as we have no information on whether 1948/1952 clocks in Tijuana followed # the decrees or followed San Diego. @@ -2827,9 +2841,7 @@ Zone America/Tijuana -7:48:04 - LMT 1922 Jan 1 7:00u -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 + -8:00 CA P%sT 1967 -8:00 US P%sT 1996 -8:00 Mexico P%sT 2001 -8:00 US P%sT 2002 Feb 20 -- 2.48.1