From 8e7dcafc27d697c51dda77bb8804d62eda033c04 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Sat, 7 Mar 2026 00:11:29 -0800 Subject: [PROPOSED] Delay America/Vancouver tm_isdst transition Requested for CLDR by Robert Bastian in: https://lists.iana.org/hyperkitty/list/tz@iana.org/thread/IEZR4HYQXZTUMGRA7FEZJAKAOGFGOPIP/ Also, use "MST" rather than "-07" as the abbreviation. * NEWS: Adjust accordingly. * northamerica (America/Vancouver): As a temporary hack, model the change as occurring on 2026-11-01 02:00, not on 2026-03-09. Also, use "MST" rather than "-07". * zone.tab, zone1970.tab, zonenow.tab: Adjust comments accordingly. --- NEWS | 11 +++++++---- northamerica | 29 +++++++++++++++++++++-------- zone.tab | 2 +- zone1970.tab | 2 +- zonenow.tab | 4 ++-- 5 files changed, 32 insertions(+), 16 deletions(-) diff --git a/NEWS b/NEWS index 3ed61963..267e62da 100644 --- a/NEWS +++ b/NEWS @@ -4,10 +4,13 @@ Unreleased, experimental changes Changes to future timestamps - On 2026-03-09 British Columbia will go from daylight to standard - time, without a UT offset change. That is, its 2026-03-08 spring - forward will be its last foreseeable clock change, as it will move - to permanent -07 thereafter. (Thanks to Arthur David Olson.) + British Columbia's 2026-03-08 spring forward will be its last + foreseeable clock change, as it moves to permanent -07 thereafter. + (Thanks to Arthur David Olson.) Although the change to permanent + -07 legally takes place on 2026-03-09, temporarily model the + change to occur on 2026-11-01 at 02:00 instead. This works around + a limitation in CLDR v48.1 (2026-01-08). This temporary hack is + planned to be removed after CLDR is fixed. Release 2026a - 2026-03-01 22:59:49 -0800 diff --git a/northamerica b/northamerica index 815fda14..ee0dc50a 100644 --- a/northamerica +++ b/northamerica @@ -1962,22 +1962,32 @@ Zone America/Edmonton -7:33:52 - LMT 1906 Sep # on March 8 will be the last time change, ending twice-yearly clock changes.” # https://news.gov.bc.ca/releases/2026AG0013-000209 # -# From Paul Eggert (2026-03-03): -# The law specifies a 2026-03-08 02:00 switch from PST to PDT, then 21 hours -# of PDT, then a 2026-03-09 switch to the new standard time Pacific Time, +# From Paul Eggert (2026-03-07): +# The law says that 21 hours after the usual 2026-03-08 02:00 switch from +# PST to PDT, the next day inaugurates the new standard time Pacific Time, # i.e., just one clock change but two name changes separated by 21 hours. -# # PT, the obvious abbreviation for Pacific Time, is one letter too short # to conform to TZDB’s (and POSIX’s) [-+[:alnum:]]{3,6} requirements. -# I asked the BC government for advice, with no response yet. -# For now, use the abbreviation -07; we can decide later what (if any) -# conforming non-numeric abbreviation to use. Possibilities include: +# I asked the BC government for advice, with no response. For now, do this: +# 1. As a temporary hack, pretend that the BC law takes effect +# not on 2026-03-09 at 00:00, but on 2026-11-01 at 02:00. +# This pretense works around a limitation in CLDR v48.1 (2026-01-08), +# which would otherwise say the interval uses “Pacific Standard Time”. +# (Below, this temporary hack is marked “Temporary hack; see above.”) +# Strictly speaking this hack is incorrect since the interval uses +# standard time, but it does have the right UT offset and it +# works around the CLDR limitation. We should be able to remove +# the temporary hack after CLDR is fixed. +# 2. After the BC law takes effect, model the time as MST sans DST. +# We can change this later if another conforming non-numeric abbreviation +# for Pacific Time becomes more popular. Possibilities include: # MST - the most compatible with existing software and practice, # and already used in parts of BC and in Yukon # PDT - almost as software-friendly, but confusing because it implies # it is DST and is paired with PST, whereas PT is standard time # PST - straightforward but even more confusing, # and will likely break much software that assumes PST is -08 +# -07 - accurate and clear in itself, but makes BC look odd vs neighbors # CPT, CPST - for Canadian Pacific (Standard) Time, # by analogy with AEST in Australia # P-T - conforming approximation to “PT” @@ -1997,7 +2007,10 @@ Rule Vanc 1962 2006 - Oct lastSun 2:00 0 S Zone America/Vancouver -8:12:28 - LMT 1884 -8:00 Vanc P%sT 1987 -8:00 Canada P%sT 2026 Mar 9 - -7:00 - -07 + # Temporary hack; see above. + -8:00 1:00 PDT 2026 Nov 1 02:00 + # End of temporary hack. + -7:00 - MST Zone America/Dawson_Creek -8:00:56 - LMT 1884 -8:00 Canada P%sT 1947 -8:00 Vanc P%sT 1972 Aug 30 2:00 diff --git a/zone.tab b/zone.tab index 2626b055..d74dfd86 100644 --- a/zone.tab +++ b/zone.tab @@ -129,7 +129,7 @@ CA +5546-12014 America/Dawson_Creek MST - BC (Dawson Cr, Ft St John) CA +5848-12242 America/Fort_Nelson MST - BC (Ft Nelson) CA +6043-13503 America/Whitehorse MST - Yukon (east) CA +6404-13925 America/Dawson MST - Yukon (west) -CA +4916-12307 America/Vancouver Pacific - BC (most areas) +CA +4916-12307 America/Vancouver British Columbia (most areas) CC -1210+09655 Indian/Cocos CD -0418+01518 Africa/Kinshasa Dem. Rep. of Congo (west) CD -1140+02728 Africa/Lubumbashi Dem. Rep. of Congo (east) diff --git a/zone1970.tab b/zone1970.tab index cd43e3d2..104c3efe 100644 --- a/zone1970.tab +++ b/zone1970.tab @@ -119,7 +119,7 @@ CA +5546-12014 America/Dawson_Creek MST - BC (Dawson Cr, Ft St John) CA +5848-12242 America/Fort_Nelson MST - BC (Ft Nelson) CA +6043-13503 America/Whitehorse MST - Yukon (east) CA +6404-13925 America/Dawson MST - Yukon (west) -CA +4916-12307 America/Vancouver Pacific - BC (most areas) +CA +4916-12307 America/Vancouver British Columbia (most areas) CH,DE,LI +4723+00832 Europe/Zurich Büsingen CI,BF,GH,GM,GN,IS,ML,MR,SH,SL,SN,TG +0519-00402 Africa/Abidjan CK -2114-15946 Pacific/Rarotonga diff --git a/zonenow.tab b/zonenow.tab index 76465722..9f01a9f9 100644 --- a/zonenow.tab +++ b/zonenow.tab @@ -58,8 +58,8 @@ XX -2504-13005 Pacific/Pitcairn Pitcairn # -08/-07 - PST/PDT (North America DST) XX +340308-1181434 America/Los_Angeles Pacific (PST/PDT) - US & Canada; Mexico near US border # -# -08/-07 - PST/PDT (British Columbia DST) until 2026-03-09; then -07 -XX +4916-12307 America/Vancouver Pacific - BC (most areas) +# -08/-07 - PST/PDT (North America DST) until 2026-11-01 02:00; then MST +XX +4916-12307 America/Vancouver British Columbia (most areas) # # -07 - MST XX +332654-1120424 America/Phoenix Mountain Standard (MST) - Arizona; western Mexico; Yukon -- 2.51.0