[tz] Turkey rules

[Brian Inglis]

On 2019-09-12 20:21, Zoidiasoft Technologies wrote:
> Just wondering how to interpret the following:
> Rule	Turkey	1977	1978	-	Apr	Sun>=1	2:00	1:00	S
> Rule	Turkey	1977	1978	-	Oct	Sun>=15	2:00	0	-
> Rule	Turkey	1978	only	-	Jun	29	0:00	0	-
> The problem is with 1978 which seems to have two end dates for DST. Knowing 
> this country has Ramadan, did I miss a rule for standard time onset at the
> start of Ramadan in 1978?

Elections are another major source of interference with the regular timing of
daylight saving transitions.

RTSL: especially the tzdata/europe Turkey comments, and also the Istanbul zone
data, not just the Turkey rules:

# http://www.resmigazete.gov.tr/arsiv/16245.pdf#page=17
# This cancels the previous decision, and repeats it only for 1978.
# 1978-04-02 02:00 -> 03:00, 1978-10-15 02:00 -> 01:00
# (not applied due to standard TZ change below)
#
# http://www.resmigazete.gov.tr/arsiv/16331.pdf#page=3
# This decision changes the default longitude for Turkish time zone from 30
# degrees East to 45 degrees East.  This means a standard TZ change, from +2
# to +3.  This is published & applied on 1978-06-29.  At that time, Turkey was
# already on summer time (already on 45E).  Hence, this new law just meant an
# "continuous summer time".  Note that this was reversed in a few years.

# Zone  NAME            STDOFF  RULES   FORMAT  [UNTIL]
Zone    Europe/Istanbul 1:55:52 -       LMT     1880
                        1:56:56 -       IMT     1910 Oct # Istanbul Mean Time?
                        2:00    Turkey  EE%sT   1978 Jun 29
                        3:00    Turkey  +03/+04 1984 Nov  1  2:00

$ zdump -Vc1978,1979 Europe/Istanbul
Europe/Istanbul  Sat Apr  1 21:59:59 1978 UT = Sat Apr  1 23:59:59 1978 EET
isdst=0 gmtoff=7200
Europe/Istanbul  Sat Apr  1 22:00:00 1978 UT = Sun Apr  2 01:00:00 1978 EEST
isdst=1 gmtoff=10800
Europe/Istanbul  Sat Oct 14 20:59:59 1978 UT = Sat Oct 14 23:59:59 1978 EEST
isdst=1 gmtoff=10800
Europe/Istanbul  Sat Oct 14 21:00:00 1978 UT = Sun Oct 15 01:00:00 1978 +04
isdst=1 gmtoff=14400

-- 
Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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