Change in Mongolian daylight saving time

Ganbold ganbold at
Sat Apr 17 07:15:51 UTC 2004

Hi Paul,

At 02:20 PM 17.04.2004, you wrote:
>At Sat, 17 Apr 2004 11:30:25 +0900, Ganbold <ganbold at> writes:
> > Last time the rule was changed in 2001 only.
>Thanks for the clarification.
>The current tz data for Mongolia in 2001 relies on this comment:
># From Rives McDow (2001-05-13):
># In addition to Mongolia starting daylight savings as reported earlier
># (adopted DST on 2001-04-27 02:00 local time, ending 2001-09-28),
>This conflicts with the rules that you mentioned, in two ways.

Yes, I agree.

>First, according to McDow the 2001 daylight-saving began on April 27,
>which was a Friday, not a Saturday; and daylight-saving ended on
>the last Friday in September, not the last Saturday.

I don't remember when daylight savings started in 2001. Probably it was on 
April 27.
Maybe McDow is confused about the day. Usually daylight saving started last 
Saturday 2:00AM by local
Mongolian time. It means 6:00PM by GMT/UTC Friday.

>It's possible that McDow's informant got confused about Friday versus
>Saturday; it wouldn't be the first time that this has happened.  But
>the part about the end of April sounds plausible -- it's quite common
>for countries to start daylight-saving late their first year.


>unless you disagree, I'm inclined to change the rules to be the
>Rule    Mongol  2001    only    -       Apr     lastSat 2:00    1:00    S
>Rule    Mongol  2001    max     -       Sep     lastSat 2:00    0       -
>Rule    Mongol  2002    max     -       Mar     lastSat 2:00    1:00    S
>i.e., from the last Saturday in March at 02:00 to the last Saturday in
>September in 02:00, except that in 2001 it didn't start until the last
>Saturday in April.

I agree with it. One more question, maybe this is off topic. How to make
time synchronization? I installed ntp daemon which makes synchronization from
some public time servers. However because of daylight saving time it is 
still off by 1 hour.
That's why I started looking at /usr/src/share/zoneinfo/asia file and found 
out wrong rules for Mongolia.
Can you give me some advice and solution to make time synchronization which 
counts daylight saving?

thanks in advance,


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