Asia/Irkutsk

Time zone identifier: Asia/Irkutsk

Current civil offset: +08:00 (+08)

Current DST state: Observing Standard Time

First standard time adoption: Adopted on 1879-12-31

Local Mean Time (LMT): +06:57:05 based on geographic meridian

Total recorded transitions: 66 transitions across 4 distinct offsets

Associated countries: RU

Historical Offset Step Chart (1880 to Present)

Text summary: Asia/Irkutsk shifted between 4 distinct offsets from 1879-12-31 through the modern era.

Complete Transition History (66 Transitions)

UTC Instant	Local Wall Time	Shift	Abbreviation	DST	Effect
`1879-12-31T17:02:55Z`	`1880-01-01 00:00:00`	+06:57:05 → +06:57:05	`IMT`	No	offset-only
`1920-01-24T17:02:55Z`	`1920-01-25 00:02:55`	+06:57:05 → +07:00	`+07`	No	gap
`1930-06-20T17:00:00Z`	`1930-06-21 01:00:00`	+07:00 → +08:00	`+08`	No	gap
`1981-03-31T16:00:00Z`	`1981-04-01 01:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1981-09-30T15:00:00Z`	`1981-09-30 23:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1982-03-31T16:00:00Z`	`1982-04-01 01:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1982-09-30T15:00:00Z`	`1982-09-30 23:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1983-03-31T16:00:00Z`	`1983-04-01 01:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1983-09-30T15:00:00Z`	`1983-09-30 23:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1984-03-31T16:00:00Z`	`1984-04-01 01:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1984-09-29T18:00:00Z`	`1984-09-30 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1985-03-30T18:00:00Z`	`1985-03-31 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1985-09-28T18:00:00Z`	`1985-09-29 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1986-03-29T18:00:00Z`	`1986-03-30 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1986-09-27T18:00:00Z`	`1986-09-28 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1987-03-28T18:00:00Z`	`1987-03-29 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1987-09-26T18:00:00Z`	`1987-09-27 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1988-03-26T18:00:00Z`	`1988-03-27 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1988-09-24T18:00:00Z`	`1988-09-25 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1989-03-25T18:00:00Z`	`1989-03-26 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1989-09-23T18:00:00Z`	`1989-09-24 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1990-03-24T18:00:00Z`	`1990-03-25 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1990-09-29T18:00:00Z`	`1990-09-30 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1991-03-30T18:00:00Z`	`1991-03-31 02:00:00`	+08:00 → +08:00	`+08`	Yes	offset-only
`1991-09-28T19:00:00Z`	`1991-09-29 02:00:00`	+08:00 → +07:00	`+07`	No	overlap
`1992-01-18T19:00:00Z`	`1992-01-19 03:00:00`	+07:00 → +08:00	`+08`	No	gap
`1992-03-28T18:00:00Z`	`1992-03-29 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1992-09-26T18:00:00Z`	`1992-09-27 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1993-03-27T18:00:00Z`	`1993-03-28 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1993-09-25T18:00:00Z`	`1993-09-26 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1994-03-26T18:00:00Z`	`1994-03-27 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1994-09-24T18:00:00Z`	`1994-09-25 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1995-03-25T18:00:00Z`	`1995-03-26 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1995-09-23T18:00:00Z`	`1995-09-24 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1996-03-30T18:00:00Z`	`1996-03-31 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1996-10-26T18:00:00Z`	`1996-10-27 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1997-03-29T18:00:00Z`	`1997-03-30 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1997-10-25T18:00:00Z`	`1997-10-26 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1998-03-28T18:00:00Z`	`1998-03-29 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1998-10-24T18:00:00Z`	`1998-10-25 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`1999-03-27T18:00:00Z`	`1999-03-28 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`1999-10-30T18:00:00Z`	`1999-10-31 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`2000-03-25T18:00:00Z`	`2000-03-26 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`2000-10-28T18:00:00Z`	`2000-10-29 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`2001-03-24T18:00:00Z`	`2001-03-25 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`2001-10-27T18:00:00Z`	`2001-10-28 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`2002-03-30T18:00:00Z`	`2002-03-31 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`2002-10-26T18:00:00Z`	`2002-10-27 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`2003-03-29T18:00:00Z`	`2003-03-30 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`2003-10-25T18:00:00Z`	`2003-10-26 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`2004-03-27T18:00:00Z`	`2004-03-28 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`2004-10-30T18:00:00Z`	`2004-10-31 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`2005-03-26T18:00:00Z`	`2005-03-27 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`2005-10-29T18:00:00Z`	`2005-10-30 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`2006-03-25T18:00:00Z`	`2006-03-26 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`2006-10-28T18:00:00Z`	`2006-10-29 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`2007-03-24T18:00:00Z`	`2007-03-25 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`2007-10-27T18:00:00Z`	`2007-10-28 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`2008-03-29T18:00:00Z`	`2008-03-30 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`2008-10-25T18:00:00Z`	`2008-10-26 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`2009-03-28T18:00:00Z`	`2009-03-29 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`2009-10-24T18:00:00Z`	`2009-10-25 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`2010-03-27T18:00:00Z`	`2010-03-28 03:00:00`	+08:00 → +09:00	`+09`	Yes	gap
`2010-10-30T18:00:00Z`	`2010-10-31 02:00:00`	+09:00 → +08:00	`+08`	No	overlap
`2011-03-26T18:00:00Z`	`2011-03-27 03:00:00`	+08:00 → +09:00	`+09`	No	gap
`2014-10-25T17:00:00Z`	`2014-10-26 01:00:00`	+09:00 → +08:00	`+08`	No	overlap

Notes from the Maintainers

Source: europe (Lines 3276 to 3289)

From Tim Parenti (2014-07-03), per Oscar van Vlijmen (2001-08-25):
Asia/Irkutsk covers...
03	RU-BU	Buryatia, Republic of
38	RU-IRK	Irkutsk Oblast

Note: Effective 2008-01-01, (85) Ust-Orda Buryat Autonomous Okrug was
merged into (38, RU-IRK) Irkutsk Oblast.

Milne 1899 says Irkutsk was 6:57:15.
Byalokoz 1919 says Irkutsk was 6:57:05.
Go with Byalokoz.

Attributed Statements:

Tim Parenti (2014-07-03):

Asia/Irkutsk covers... 03 RU-BU Buryatia, Republic of 38 RU-IRK Irkutsk Oblast Note: Effective 2008-01-01, (85) Ust-Orda Buryat Autonomous Okrug was merged into (38, RU-IRK) Irkutsk Oblast. Milne 1899 says Irkutsk was 6:57:15. Byalokoz 1919 says Irkutsk was 6:57:05. Go with Byalokoz.

Years on Record

Methodology Note: The 1970 Rule

tzdb guarantees accuracy for timestamps from 1970 onwards. Transitions prior to 1970 represent best-effort historical reconstructions.