On 2025-06-18 19:03, Collin Funk via tz wrote:
Dan Juskevicius via tz writes:
I'm currently working on an issue that one of our customers has
reported with the tz database. Using the latest release (2025b), I
have been able to reproduce an issue with America/Nuuk time where it
reports at -02 instead of -01; I realize that as of 2023-03-25 the
America/Nuuk time zone changed its standard time from -03 to -02, but
it appears that it is not represented correctly in the tzdb. All other
time zones in the database appear to be represented correctly, so I'm
trying to narrow down the root cause of the issue but don't know where
to look.
Has anyone else reported issue with the America/Nuuk tz, and if so, is there a
workaround for this?
I think that change was handled in 2022 [1].
I see that -01 is used on my system with tzdb 2025b.
$ rpm -qa | grep tzdata | sed 1q
tzdata-2025b-1.fc42.noarch
$ TZ='America/Nuuk' date --iso-8601=m
2025-06-19T00:00-01:00
[1]
https://lists.iana.org/hyperkitty/list/[email protected]/message/KWCZPPK7EWDBCAYTT5BZZKR5UMYR3QLF/
Perhaps the issue is tzdata format 3:
$ head -c20 /usr/share/zoneinfo/America/Nuuk; echo; \
tail -1 /usr/share/zoneinfo/America/Nuuk
TZif3
<-02>2<-01>,M3.5.0/-1,M10.5.0/0
$ MANWIDTH=72 man tzfile | awk '/^\s+Version\s3\sformat/,/^$/'
Version 3 format
For version‐3‐format timezone files, a TZ string (see
newtzset(3)) may use the following POSIX.1‐2024 extensions to
POSIX.1‐2017: First, as in TZ="<-02>2<-01>,M3.5.0/-1,M10.5.0/0",
the hours part of its transition times may be signed and range
from -167 through 167 instead of being limited to unsigned val‐
ues from 0 through 24. Second, as in TZ="XXX3EDT4,0/0,J365/23",
DST is in effect all year if it starts January 1 at 00:00 and
ends December 31 at 24:00 plus the difference between daylight
saving and standard time.
Main changes appear to be in 2022g & 2023a:
$ grep -h -B1 -A3 Nuuk tzdata20{22g,23a}/europe # trimmed
# From Jonas Nyrup (2022-11-24):
# On last Saturday in October 2023 when DST ends America/Nuuk will switch
# from -03/-02 to -02/-01
--
# Greenland will not go back to winter time in fall 2023, and that
# only America/Nuuk is affected (though further changes may occur).
--
Zone America/Nuuk -3:26:56 - LMT 1916 Jul 28 # Godthåb
-3:00 - -03 1980 Apr 6 2:00
-3:00 EU -03/-02 2023 Mar 25 22:00
-2:00 - -02
--
# From Thomas M. Steenholdt (2022-12-02):
# - The bill to move America/Nuuk from UTC-03 to UTC-02 passed.
# - The bill to stop observing DST did not (Greenland will stop observing DST
# when EU does).
--
Zone America/Nuuk -3:26:56 - LMT 1916 Jul 28 # Godthåb
-3:00 - -03 1980 Apr 6 2:00
-3:00 EU -03/-02 2023 Oct 29 1:00u
-2:00 EU -02/-01
--
Take care. Thanks, Brian Inglis Calgary, Alberta, Canada
La perfection est atteinte Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add
mais lorsqu'il n'y a plus rien à retrancher but when there is no more to cut
-- Antoine de Saint-Exupéry
