Iran Standard Time


Iran Standard Time or Iran Time is the time zone used in Iran. Iran uses a UTC offset. IRST is defined by the 52.5 degrees east meridian, the same meridian which defines the Iranian calendar and is the official meridian of Iran.
Between 2005 and 2008, by decree of President Mahmoud Ahmadinejad, Iran did not observe daylight saving time. It was reintroduced from 21 March 2008.

Daylight Saving Time transitions

The dates of DST transitions in Iran are based on the Solar Hijri calendar, the official calendar of Iran, which is in turn based on the March equinox as determined by astronomical calculation at the meridian for Iran Standard Time. This results in the unusual situation wherein the dates of DST transitions don't fall on the same weekday each year as they do in most other countries.
DST starts in Iran at 24:00 on 1 Farvardin, which corresponds to either 20 or 21 March in the Gregorian calendar, depending on the precise timing of the equinox. Clocks move forward at that time to 01:00 on 2 Farvardin. This spring change takes place at the end of the day of Nowruz, which is the Iranian New Year's Day and the most important festival in Iranian culture.
DST likewise ends in Iran at 24:00 on 30 Shahrivar, which corresponds to either 20 or 21 September. . Clocks move backward to 23:00 on 30 Shahrivar.

Recent and upcoming dates

YearDST StartDST End
2017Wed, Mar 22, 00:00Fri, Sep 22, 00:00
2018Thu, Mar 22, 00:00Sat, Sep 22, 00:00
2019Fri, Mar 22, 00:00Sun, Sep 22, 00:00
2020Sat, Mar 21, 00:00Mon, Sep 21, 00:00
2021Mon, Mar 22, 00:00Wed, Sep 22, 00:00
2022Tue, Mar 22, 00:00Thu, Sep 22, 00:00
2023Wed, Mar 22, 00:00Fri, Sep 22, 00:00

Time zone changes

IANA time zone database

The IANA time zone database contains one zone for Iran in the file zone.tab, named Asia/Tehran.