Iran Standard Time (IRST) or Iran Time (IT) is the time zone used in Iran. Iran uses a UTC offset UTC+03:30. 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 (called Iran Daylight Time or IRDT). It was reintroduced from 21 March 2008, enforced by the Iranian Parliament.
IANA time zone database
The IANA time zone database contains one zone for Iran in the file zone.tab, named Asia/Tehran.