Thanks for that research on Baja California. I installed the attached
proposed patches. The first one is for Baja California and goes back to
what Shanks said about Tijuana, as this agrees with your data. The
second one is commentary about Zapotec timekeeping which I found while
looking into the matter.From 8185dfc1fba1791df5936b700cdef6cc85e3e0dd Mon Sep 17 00:00:00 2001
From: Paul Eggert <[email protected]>
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
From df8a67797952555d3be1b779739accfbf5e785a3 Mon Sep 17 00:00:00 2001
From: Paul Eggert <[email protected]>
Date: Mon, 4 Aug 2025 09:09:25 -0700
Subject: [PROPOSED 2/2] Add Schapiro notes on Zapotec timekeeping
* northamerica: New comments.
---
northamerica | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/northamerica b/northamerica
index c29ab9fd..bb3d1b43 100644
--- a/northamerica
+++ b/northamerica
@@ -2464,6 +2464,15 @@ Zone America/Dawson -9:17:40 - LMT 1900 Aug 20
# as we have no information on whether 1948/1952 clocks in Tijuana followed
# the decrees or followed San Diego.
+# From Mark Schapiro, writing in The Nation (2002-10-28):
+# https://www.thenation.com/article/archive/sowing-disaster/
+# When Mexican clocks were turned back for daylight saving time in the spring,
+# the Zapotecs refused to make the adjustment, insisting that they live in
+# "God's time," not in what they derisively call "Fox time," referring to
+# President Vicente Fox in far-off Mexico City.
+# From Paul Eggert (2025-08-04):
+# Unfortunately we have no data to track this informal practice.
+
# From Alan Perry (1996-02-15):
# A guy from our Mexico subsidiary finally found the Presidential Decree
# outlining the timezone changes in Mexico.
--
2.48.1
