Date: Sat, 15 Mar 2003 13:07:13 +0330 (IRT) From: Roozbeh Pournader <roozbeh@sharif.edu>
Iran's daylight saving time is one day off.
Thanks a lot for reporting this, along with the official source. I enclose below a revised patch, which I consider to be a supplement to my March 13 proposed patches to the overall tz database. I have modified your patch as follows: * Update commentary to mention the official source that you mentioned, along with your "IRST/IRDT" remark. Remove commentary mentioning some lower-quality sources that are no longer used. * Change the September 1991 transition from September 20 to September 22. That is, I'd guess from the timing of your official announcement that the change took effect before the September 1991 transition, not after that transition. * Use "IRST" (not "IRT") for standard time in Iran between 1946 and 1977.
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.
This doesn't match the Shanks data well, but as you mentioned we can wait on correcting the pre-1991 transitions until we get more authoritative sources. Thanks again. --- asia 2003/03/14 04:28:08 2002.4.0.1 +++ asia 2003/03/16 05:17:32 2002.4.0.2 @@ -29,22 +29,23 @@ # I invented the abbreviations marked `*' in the following table; # the rest are from earlier versions of this file, or from other sources. # Corrections are welcome! -# std dst -# LMT Local Mean Time -# 2:00 EET EEST Eastern European Time -# 2:00 IST IDT Israel -# 3:00 AST ADT Arabia* -# 4:00 GST Gulf* -# 5:30 IST India -# 7:00 ICT Indochina* -# 7:00 WIT west Indonesia -# 8:00 CIT central Indonesia -# 8:00 CST China -# 9:00 CJT Central Japanese Time (1896/1937)* -# 9:00 EIT east Indonesia -# 9:00 JST Japan -# 9:00 KST Korea -# 9:30 CST (Australian) Central Standard Time +# std dst +# LMT Local Mean Time +# 2:00 EET EEST Eastern European Time +# 2:00 IST IDT Israel +# 3:00 AST ADT Arabia* +# 3:30 IRST IRDT Iran +# 4:00 GST Gulf* +# 5:30 IST India +# 7:00 ICT Indochina* +# 7:00 WIT west Indonesia +# 8:00 CIT central Indonesia +# 8:00 CST China +# 9:00 CJT Central Japanese Time (1896/1937)* +# 9:00 EIT east Indonesia +# 9:00 JST Japan +# 9:00 KST Korea +# 9:30 CST (Australian) Central Standard Time # # See the `europe' file for Russia and Turkey in Asia. @@ -430,89 +431,97 @@ Zone Asia/Jayapura 9:22:48 - LMT 1932 No 9:00 - EIT # Iran -# From Paul Eggert (2000-06-12), following up a suggestion by Rich Wales: -# Ahmea Alavi in -# <a href="http://www.persia.org/Iran_Lib/Calendar/taghveem.txt"> -# TAGHVEEM (1993-07-12) -# </a> -# writes ``Daylight saving time in Iran starts from the first day -# of Farvardin and ends the first day of Mehr.'' This disagrees with the SSIM: -# -# DST start DST end -# year SSIM Alavi SSIM Alavi -# 1991 05-03!= 03-21 09-20!= 09-23 -# 1992 03-22!= 03-21 09-23 09-23 -# 1993 03-21 03-21 09-23 09-23 -# 1994 03-21 03-21 09-22!= 09-23 -# 1995 03-21 03-21 09-22!= 09-23 -# 1996 03-21!= 03-20 09-22 09-22 -# 1997 03-22!= 03-21 09-22!= 09-23 -# 1998 03-21 03-21 09-21!= 09-23 -# 1999 03-22!= 03-21 09-22!= 09-23 -# 2000 03-21!= 03-20 09-21!= 09-22 -# 2001 03-19!= 03-21 09-19!= 09-23 -# 2002 03-18!= 03-21 09-18!= 09-23 -# -# Go with Alavi starting with 1992. -# I used Ed Reingold's cal-persia in GNU Emacs 19.34 to compute Persian dates. + +# From Roozbeh Pournader (2003-03-15): +# This is an English translation of what I just found (originally in +Persian). # The Gregorian dates in brackets are mine: # +# 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 +# +# 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 have also changed the abbreviations to what is considered correct +# here in Iran, IRST for regular time and IRDT for daylight saving time. + +# From Paul Eggert (2003-03-15) +# Go with Shanks before September 1991, and with Pourander thereafter. +# I used Ed Reingold's cal-persia in GNU Emacs 21.2 to check Persian +dates. # The Persian calendar is based on the sun, and dates after around 2050 # are approximate; stop after 2037 when 32-bit time_t's overflow. # # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S -Rule Iran 1978 1980 - Mar 21 0:00 1:00 S -Rule Iran 1978 only - Oct 21 0:00 0 - -Rule Iran 1979 only - Sep 19 0:00 0 - -Rule Iran 1980 only - Sep 23 0:00 0 - -Rule Iran 1991 only - May 3 0:00s 1:00 S -Rule Iran 1991 only - Sep 20 0:00s 0 - -Rule Iran 1992 1995 - Mar 21 0:00 1:00 S -Rule Iran 1992 1995 - Sep 23 0:00 0 - -Rule Iran 1996 only - Mar 20 0:00 1:00 S -Rule Iran 1996 only - Sep 22 0:00 0 - -Rule Iran 1997 1999 - Mar 21 0:00 1:00 S -Rule Iran 1997 1999 - Sep 23 0:00 0 - -Rule Iran 2000 only - Mar 20 0:00 1:00 S -Rule Iran 2000 only - Sep 22 0:00 0 - -Rule Iran 2001 2003 - Mar 21 0:00 1:00 S -Rule Iran 2001 2003 - Sep 23 0:00 0 - -Rule Iran 2004 only - Mar 20 0:00 1:00 S -Rule Iran 2004 only - Sep 22 0:00 0 - -Rule Iran 2005 2007 - Mar 21 0:00 1:00 S -Rule Iran 2005 2007 - Sep 23 0:00 0 - -Rule Iran 2008 only - Mar 20 0:00 1:00 S -Rule Iran 2008 only - Sep 22 0:00 0 - -Rule Iran 2009 2011 - Mar 21 0:00 1:00 S -Rule Iran 2009 2011 - Sep 23 0:00 0 - -Rule Iran 2012 only - Mar 20 0:00 1:00 S -Rule Iran 2012 only - Sep 22 0:00 0 - -Rule Iran 2013 2015 - Mar 21 0:00 1:00 S -Rule Iran 2013 2015 - Sep 23 0:00 0 - -Rule Iran 2016 only - Mar 20 0:00 1:00 S -Rule Iran 2016 only - Sep 22 0:00 0 - -Rule Iran 2017 2019 - Mar 21 0:00 1:00 S -Rule Iran 2017 2019 - Sep 23 0:00 0 - -Rule Iran 2020 only - Mar 20 0:00 1:00 S -Rule Iran 2020 only - Sep 22 0:00 0 - -Rule Iran 2021 2023 - Mar 21 0:00 1:00 S -Rule Iran 2021 2023 - Sep 23 0:00 0 - -Rule Iran 2024 2025 - Mar 20 0:00 1:00 S -Rule Iran 2024 2025 - Sep 22 0:00 0 - -Rule Iran 2026 2027 - Mar 21 0:00 1:00 S -Rule Iran 2026 2027 - Sep 23 0:00 0 - -Rule Iran 2028 2029 - Mar 20 0:00 1:00 S -Rule Iran 2028 2029 - Sep 22 0:00 0 - -Rule Iran 2030 2031 - Mar 21 0:00 1:00 S -Rule Iran 2030 2031 - Sep 23 0:00 0 - -Rule Iran 2032 2033 - Mar 20 0:00 1:00 S -Rule Iran 2032 2033 - Sep 22 0:00 0 - -Rule Iran 2034 2035 - Mar 21 0:00 1:00 S -Rule Iran 2034 2035 - Sep 23 0:00 0 - -Rule Iran 2036 2037 - Mar 20 0:00 1:00 S -Rule Iran 2036 2037 - Sep 22 0:00 0 - +Rule Iran 1978 1980 - Mar 21 0:00 1:00 D +Rule Iran 1978 only - Oct 21 0:00 0 S +Rule Iran 1979 only - Sep 19 0:00 0 S +Rule Iran 1980 only - Sep 23 0:00 0 S +Rule Iran 1991 only - May 3 0:00 1:00 D +Rule Iran 1992 1995 - Mar 22 0:00 1:00 D +Rule Iran 1991 1995 - Sep 22 0:00 0 S +Rule Iran 1996 only - Mar 21 0:00 1:00 D +Rule Iran 1996 only - Sep 21 0:00 0 S +Rule Iran 1997 1999 - Mar 22 0:00 1:00 D +Rule Iran 1997 1999 - Sep 22 0:00 0 S +Rule Iran 2000 only - Mar 21 0:00 1:00 D +Rule Iran 2000 only - Sep 21 0:00 0 S +Rule Iran 2001 2003 - Mar 22 0:00 1:00 D +Rule Iran 2001 2003 - Sep 22 0:00 0 S +Rule Iran 2004 only - Mar 21 0:00 1:00 D +Rule Iran 2004 only - Sep 21 0:00 0 S +Rule Iran 2005 2007 - Mar 22 0:00 1:00 D +Rule Iran 2005 2007 - Sep 22 0:00 0 S +Rule Iran 2008 only - Mar 21 0:00 1:00 D +Rule Iran 2008 only - Sep 21 0:00 0 S +Rule Iran 2009 2011 - Mar 22 0:00 1:00 D +Rule Iran 2009 2011 - Sep 22 0:00 0 S +Rule Iran 2012 only - Mar 21 0:00 1:00 D +Rule Iran 2012 only - Sep 21 0:00 0 S +Rule Iran 2013 2015 - Mar 22 0:00 1:00 D +Rule Iran 2013 2015 - Sep 22 0:00 0 S +Rule Iran 2016 only - Mar 21 0:00 1:00 D +Rule Iran 2016 only - Sep 21 0:00 0 S +Rule Iran 2017 2019 - Mar 22 0:00 1:00 D +Rule Iran 2017 2019 - Sep 22 0:00 0 S +Rule Iran 2020 only - Mar 21 0:00 1:00 D +Rule Iran 2020 only - Sep 21 0:00 0 S +Rule Iran 2021 2023 - Mar 22 0:00 1:00 D +Rule Iran 2021 2023 - Sep 22 0:00 0 S +Rule Iran 2024 2025 - Mar 21 0:00 1:00 D +Rule Iran 2024 2025 - Sep 21 0:00 0 S +Rule Iran 2026 2027 - Mar 22 0:00 1:00 D +Rule Iran 2026 2027 - Sep 22 0:00 0 S +Rule Iran 2028 2029 - Mar 21 0:00 1:00 D +Rule Iran 2028 2029 - Sep 21 0:00 0 S +Rule Iran 2030 2031 - Mar 22 0:00 1:00 D +Rule Iran 2030 2031 - Sep 22 0:00 0 S +Rule Iran 2032 2033 - Mar 21 0:00 1:00 D +Rule Iran 2032 2033 - Sep 21 0:00 0 S +Rule Iran 2034 2035 - Mar 22 0:00 1:00 D +Rule Iran 2034 2035 - Sep 22 0:00 0 S +Rule Iran 2036 2037 - Mar 21 0:00 1:00 D +Rule Iran 2036 2037 - Sep 21 0:00 0 S # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Asia/Tehran 3:25:44 - LMT 1916 3:25:44 - TMT 1946 # Tehran Mean Time - 3:30 - IRT 1977 Nov + 3:30 - IRST 1977 Nov 4:00 Iran IR%sT 1979 3:30 Iran IR%sT