Iran's daylight saving time is one day off. This is an English translation
of what I just found (originally in Persian). The Gregorian dates in
brackets are mine:
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Official Newspaper No. 13548-1370/6/25 [1991-09-16]
No. 16760/T233 H 1370/6/10 [1991-09-01]
The Rule About Change of the Official Time of the Country
The Board of Ministers, in the meeting dated 1370/5/23 [1991-08-14], based
on the suggestion number 2221/D dated 1370/4/22 [1991-07-13] of the
Country's Organization for Official and Employment Affairs, and referring
to the law for equating the working hours of workers and officers in the
whole country dated 1359/4/23 [1980-07-14], and for synchronizing the
official times of the country, agreed that:
The official time of the country will should move forward one hour at the
24[:00] hours of the first day of Farvardin and should return to its
previous state at the 24[:00] hours of the 30th day of Shahrivar.
First Deputy to the President - Hassan Habibi
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This affects all the tz data starting from 1992.
>From personal experience, that agrees with what has been followed for at
least the last 5 years. Before that, for a few years, the date used was
the first Thursday night of Farvardin and the last Thursday night of
Shahrivar, but I can't give exact dates. I'm searching for evidence of the
exact dates of each year in the newspaper archives.
But in the meanwhile, it'd be great to update the database with the
attached patch. Iran will be in daylight saving in just a week, and
current tz data is off one day. The new data is guaranteed to be correct
from about 1998 until the end (2037). I have also changed the
abbreivations to what is considered correct here in Iran, IRST for regular
time and IRDT for daylight saving time.
roozbeh
