Mongolia time zones

Paul Eggert eggert at
Sun May 13 19:52:46 UTC 2001

> Date: Sun, 13 May 2001 10:59:24 -0800
> From: Rives McDow <rmcdow at>

>     In addition to Mongolia starting daylight savings as reported earlier
> (adopted dst on April 27, 2001,0200 local time, ending Sept. 28, 2001),

Thanks.  Sorry, I missed that somehow.  Is this a one-time deal, or
are they permanently instituting DST, presumably using a
last-Friday-of-April-and-September rule?

> there are three time zones.

I guess it's time to add a new Asia/Choibalsan Zone.  Shanks wrote
that they diverged from Ulaanbaatar time in April 1983, so I'll assume
that.  Also, your "0200 local time" agrees with Shanks from mid-1984
on, but disagrees with the IATA; I'll assume that the IATA has been
wrong (which wouldn't be the first time).

>  Provinces 19 hours from the IDL:
> Bayan-ulgii, Uvs, Khovd, Zavkhan, Govi-Altai

<> (now inaccessible,
alas) reported in 1999-09 that only Bayan-ulgii, Uvs, and Khovd were
in that time zone.  Did the other two provinces switch zones?  They
are further west than Khovd, so for now, I'll assume that the earlier
reference missed those two provinces.  (That reference claimed that
there was no third time zone in the east, which disagreed with Shanks
and other sources, so it was on my "questionable" list anyway.)

> Provinces 20 hours from the IDL:
> Khovsgol, Bulgan, Arkhangai, Khentii, Tov, Bayankhongor, Ovorkhangai,
> Dundgovi, Dornogovi, Omnogovi,
> Provinces 21 hours from the IDL:
> Choibalsan, Sukhbaatar

Just as a point of trivia, <>
says that Choibalsan is in the province of Dornod.  Your list also
omits the province of Selenge, which is listed in that source and at
the CIA.  (Maybe they redrew the provincial lines lately?  It's such a
pain to deal with a nation that is still nearly half nomadic.  :-)

More information about the tz mailing list