Iran Standard Time (IRST) orIran Time (IT) is thetime zone used in Iran. Iran uses a UTC offsetUTC+03:30. IRST is defined by the 52.5 degrees eastmeridian, the same meridian which defines theIranian calendar and is the official meridian of Iran.
▉▉▉Standard time observed all year
▉Daylight saving time observed
Between 2005 and 2008, by decree of PresidentMahmoud Ahmadinejad, Iran did not observedaylight saving time (DST) (calledIran Daylight Time orIRDT).[1] It was reintroduced from 21 March 2008. On 21 September 2022, Iran abolished DST and now observes standard time year-round.[2][3]
Daylight Saving Time transitions
editThe dates of DST transitions in Iran were based on theSolar Hijri calendar, the official calendar ofIran, which is in turn based on theMarch equinox (Nowruz) as determined by astronomical calculation at themeridian for Iran Standard Time (52.5°E or GMT+3.5h). This resulted in the unique situation wherein the dates of DST transitions didn't fall on the same weekday each year as they do in most other countries.
DST started in Iran at 24:00 on 1Farvardin, which corresponds to either 20 or 21 March in theGregorian calendar, depending on the precise timing of the equinox. (This is equivalent to 00:00 on 2 Farvardin, either 21 or 22 March.) Clocks moved forward at that time to 01:00 on 2 Farvardin (21 or 22 March). This spring change took place at the end of the day ofNowruz, which is theIranianNew Year's Day[4] and the most important festival in Iranian culture.
DST likewise ended in Iran at 24:00 on 30Shahrivar, which corresponds to either 20 or 21 September. (Equivalently, at 00:00 on 31 Shahrivar, either 21 or 22 September). Clocks moved backward to 23:00 on 30 Shahrivar (20 or 21 September).[5][6]
Recent and upcoming dates
edit| Year[7] | DST Start | DST End |
|---|---|---|
| 2017 | Wed, Mar 22, 00:00 | Fri, Sep 22, 00:00 |
| 2018 | Thu, Mar 22, 00:00 | Sat, Sep 22, 00:00 |
| 2019 | Fri, Mar 22, 00:00 | Sun, Sep 22, 00:00 |
| 2020 | Sat, Mar 21, 00:00 | Mon, Sep 21, 00:00 |
| 2021 | Mon, Mar 22, 00:00 | Wed, Sep 22, 00:00 |
| 2022 | Tue, Mar 22, 00:00 | Thu, Sep 22, 00:00 |
Time zone changes
edit| Period in use | Time offset from GMT | Name of time |
|---|---|---|
| before 1945 | UTC+03:25:44 | Tehran Mean Time (TMT) |
| 1946 – 1977 | UTC+03:30 | Iran Standard Time (IRST) |
| 1977 – 1978 | UTC+04:00 UTC+05:00 | Iran Standard Time (IRST) Iran Daylight Time (IRDT) |
| 1979 – 1980 | UTC+03:30 UTC+04:30 | Iran Standard Time (IRST) Iran Daylight Time (IRDT) |
| 1981 – 1990 | UTC+03:30 | Iran Standard Time (IRST) |
| 1991 – 2005 | UTC+03:30 UTC+04:30 | Iran Standard Time (IRST) Iran Daylight Time (IRDT) |
| 2006 – 2007 | UTC+03:30 | Iran Standard Time (IRST) |
| 2008 – 2022 | UTC+03:30 UTC+04:30 | Iran Standard Time (IRST) Iran Daylight Time (IRDT) |
| 2022 – present | UTC+03:30 | Iran Standard Time (IRST) |
See also
edit
References
edit- ^"Time zone and daylight saving time for Iran – Tehran between 2010 and 2019". Timeanddate.com. Retrieved9 May 2010.
- ^"Iran Considers Abolishing DST".timeanddate.com. Retrieved13 May 2022.
- ^"Daylight Saving Time Ends in Iran".Livingintehran.com. 2022-09-21.
- ^"Culture of Iran: No-Rooz, The Iranian New Year at Present Times".www.iranchamber.com. Retrieved1 February 2016.
- ^Roozbeh Pournader (15 March 2003)."Iran daylight saving time correction". Retrieved1 December 2018.
- ^tz database (30 November 2018)."
asiafile, lines 1278–1299".GitHub. Retrieved1 December 2018. - ^"Time Changes in Tehran over the years".
