Time Zone History

Iran time zone history

Its standard time, UTC+3:30, is one of only 14 offsets among the 312 zones that are not a whole number of hours from UTC. Daylight saving time was used in 34 years since 1970, last in 2022; under the current rules the clocks no longer change.

UTC+3:30

Standard time is UTC+3:30 all year under the current rules.

tz database name Asia/Tehran

Convert a time from Iran

Summer time in 34 of 57 years since 1970

UTC+3:25:44: 4 minutes behind today’s standard timeUTC+3:30: today’s standard timeUTC+4: 30 minutes ahead of today’s standard timeUTC+4:30, UTC+5: ahead of today’s standard timeUTC+3:25:44: 4 minutes behindtoday’s standard timeUTC+3:30: today’s standard timeUTC+4: 30 minutes ahead of today’sstandard timeUTC+4:30, UTC+5: ahead of today’sstandard time

How to read this chart

Before 1970

19101920193019401950196019701910192019301940195019601970
JanFebMarAprMayJunJulAugSepOctNovDec1970198019902000201020202028JFMAMJJASOND1970198019902000201020202028

Standard time changes

DateChangeNew standard timeClock label
Before 1970
January 1, 1916Local mean time (UTC+3:25:44) replacedUTC+3:25:44TMT
June 13, 1935Standard time forward 4 minutesUTC+3:30numeric only
Since 1970
October 21, 1977Standard time forward 30 minutesUTC+4numeric only
November 11, 1978Standard time back 30 minutesUTC+3:30numeric only

Daylight saving periods

YearsClocks go forwardClocks go backShift and labels
1977March 21not that year1 hour
1978March 25August 51 hour
1979May 26September 191 hour
1980March 21September 231 hour
1991May 3September 221 hour
1992–199522 March, 00:0022 September, 00:001 hour
1996March 21September 211 hour
1997–199922 March, 00:0022 September, 00:001 hour
2000March 21September 211 hour
2001–200322 March, 00:0022 September, 00:001 hour
2004March 21September 211 hour
2005March 22September 221 hour
2008March 21September 211 hour
2009–201122 March, 00:0022 September, 00:001 hour
2012March 21September 211 hour
2013–201522 March, 00:0022 September, 00:001 hour
2016March 21September 211 hour
2017–201922 March, 00:0022 September, 00:001 hour
2020March 21September 211 hour
2021–202222 March, 00:0022 September, 00:001 hour

Clocks next door since 1970

  • Azerbaijan (542 km): usually 30 minutes ahead; different on 6,281 days in 1977–2022.
  • Turkmenistan (669 km): usually 1 hour 30 minutes ahead; different on 8,320 days in 1977–2005 and 2008–2022.
  • Iraq (692 km): usually 30 minutes behind; different on 5,962 days in 1977–1980 and 1982–2022.
  • Armenia (788 km): usually 30 minutes ahead; different on 7,515 days in 1977–2022.
  • Georgia (884 km): usually 30 minutes ahead; different on 7,616 days in 1977–2005 and 2008–2022.

How it compares

On standard time, clocks in Tehran run 4 minutes ahead of local mean solar time.