Time Zones of Mongolia

Basic time zone concepts

Rules currently in force

It has been reliably reported that the former Choibalsan time zone is now observing UTC+8. It's still not clear whether Choibalsan actually used to observe UTC+9. Mongolia observed daylight saving time in 2006. The Mongolian parliament canceled it in February 2007, and it has not been observed since then.

There have been conflicting reports about Mongolia's time zones. The geographical extent of the time zones, and the duration of daylight saving time, are all questionable. Recently (May 2005), there have been a number of messages on the tz mailing list reporting a change. Some Internet time zone sites follow the tz database standard; therefore, they show Mongolia divided into three time zones as listed in the following table. Three Mongolian travel sites (Mongolian Tourism Association, Mongolian Airlines, and Tsolmon Travel), and the site of the Mongolian Embassy  in the U.S., all say that Mongolia has two time zones, with the western zone consisting of Bayan-Ölgiy, Hovd, and Uvs provinces. When the UB Post  online newspaper reported the date for the beginning of DST in March 2005, a reader wrote that there are four time zones, with Sühbaatar province on UTC+8.5 standard time. He added, "The [Sühbaatar] timezone is new this year, it is one of the few things the new parliament passed during the tumultous winter session." The OAG and the CIA World Factbook show only one time zone covering all of Mongolia, as they have done for years.

In summary, the opinions that have come forth are that Mongolia has: (a) one time zone, UTC+8; (b) two time zones, UTC+7 and UTC+8; (c) three time zones, UTC+7, UTC+8, and UTC+9; or (d) four time zones, UTC+7, UTC+8, UTC+8.5, and UTC+9. All time zones observed DST in the summer, through 2006. Parliament canceled DST for 2007. If there is a UTC+7, it covers Bayan-Ölgiy, Hovd, and Uvs provinces, and possibly Dzavhan and Govi-Altay. If there is a UTC+8.5, it covers Sühbaatar. If there is a UTC+9, it applies to Dornod and Sühbaatar (unless the latter is in UTC+8.5).

I continue to report the time zones as listed in the tz database.

AreaStandardZone Name
Bayan-Ölgiy, Dzavhan, Govi-Altay, Hovd, Uvs provincesUTC+7Asia/Hovd
Dornod and Sühbaatar provincesUTC+9Asia/Choibalsan
Rest of MongoliaUTC+8Asia/Ulaanbaatar

Time zone history

Source: This information was adapted from the tz database. Zone names come from that database. The names don't necessarily match any names used in the "real world".

Find the Rule and Standard Time for the given time and date.

Zone NameRuleStandard TimeFinal Date
Asia/HovdLocal 1905-08-01 00:00
 UTC+61978-01-01 00:00
MongolUTC+7 
Asia/UlaanbaatarLocal 1905-08-01 00:00
 UTC+71978-01-01 00:00
MongolUTC+8 
Asia/ChoibalsanLocal 1905-08-01 00:00
 UTC+71978-01-01 00:00
 UTC+81983-04-01 00:00
MongolUTC+9 

 

Apply the Rule, using the Standard Time for the given time and place.

RuleYearsDescription
LocalAllLocal Mean Solar Time
MongolStandard Time, with DST = Standard Time + 1:00 during the following periods:
1983from April 1 at 00:00 to October 1 at 00:00
1984from April 1 at 00:00 to September 29 at 03:00
1985-1998from the last Sunday in March at 02:00 to the last Sunday in September at 03:00
2001from April 27 at 02:00 to September 28 at 02:00
2002-2006from the last Saturday in March at 02:00 to the last Saturday in September at 02:00

Time zone names

The tz database contains names and abbreviations for the Mongolian time zones. They were created by a contributor. Don't assume that these names, or anything like them, have ever been used officially in Mongolia.

    Times in the Asia/Choibalsan zone are designated Choibalsan Time (CHOT), or Choibalsan Summer Time (CHOST) when daylight saving is in effect.
    Times in the Asia/Hovd zone are designated Hovd Time (HOVT), or Hovd Summer Time (HOVST) when daylight saving is in effect.
    Times in the Asia/Ulaanbaatar zone are designated Ulaanbaatar Time (ULAT), or Ulaanbaatar Summer Time (ULAST) when daylight saving is in effect.
Back to main statoids page Last updated: 2008-11-01
Copyright © 2001, 2003, 2005, 2007, 2008 by Gwillim Law.