Recent changes to time zones reported by IATA

Paul Eggert eggert at
Sun Oct 6 20:08:12 UTC 1996

   Date: Fri, 04 Oct 1996 19:34:39 -0500 (EST)
   From: Gwillim Law 919-852-4294 <LAW at>

   I thought the tz mailing list would want to see these changes, and
   compare them to those reported by other sources.

That is a very helpful contribution; thanks.  I compared the IATA
changes with the changes reported by other tz contributors, and have
the following comments.  Later, I'll send out a draft patch reflecting
these comments, as well as all the other comments received so far.

* Armenia stopped using DST this year, according to Edgar Der-Danieliantz
  <edd at AIC.NET> (1996-05-04).  Did the IATA catch this change?

* Azerbaijan data from the IATA disagrees with both Shanks and USNO.
  I guess that the IATA is right, and that we're missing some
  transitions between 1991 and 1996.

  Azerbaijan apparently enjoys the distinction of being the first
  Asian country to use the European Union's DST rules (including
  switching at 0100 UTC).

* Brazil - You wrote:
	three states (Alagoas, Sergipe, and Tocantins) will begin
	using DST, probably on October 13, 1996.

  Could you give more details about this?  The entries that you sent
  made it look like only the DST dates were adjusted.  As far as I can
  tell from other sources, DST is observed uniformly in Brazil, even
  in the far north where the hemisphere is wrong.

  Perhaps these states used to be 2 hours behind UTC, and are now 3?
  This would agree with the map in
  <URL:>, but so
  far I've discounted that map, not only because no other sources have
  UTC-2 Brazilian mainland, but also because its line between UTC-2
  and UTC-3 is suspiciously straight.

	Also, some of the beginning and end dates for DST were
	adjusted by a week.

  You gave the change only for BR1; were the dates also changed for
  other zones in Brazil?  It would be odd if the different parts of
  Brazil had different DST dates.

  All the Brazilian transitions that we know of since 1989 are
  consistent with the rules Oct Sun>=10 00:00 and Feb Sun>=10 00:00;
  I'll propose a change to the tz rules accordingly.

* Iran

  The tz database had Iran not using DST since 1980.  For lack of
  better info I'll assume they readopted DST in 1996.

  Iran now apparently moves its clocks approximately on the equinoxes
  -- I think it's the only country to do this.

* Kazakhstan - you wrote:
	Kazakhstan, formerly unified on UTC+6 with DST, will divide
	into three zones.  They will observe UTC+4, 5, and 6, all with
	DST.  The western zone (UTC+4) consists of Aktau, Atyrau, and
	Uralsk oblasts, and the central zone is Aktyubinsk oblast.

  Andrew Evtichov <evti at> (1996-04-13) wrote that
  Kazakhstan has had multiple time zones for quite some time: at least
  2 ``always'' and 3 now.  I'd guess that the IATA SSIM is just
  catching up with this fact.

  Unfortunately, I misparsed his earlier message and thought that
  Kazakhstan had just 2 time zones now; he actually wrote that it has 3.
  I'll add a new zone for Aqtobe (formerly Aktyubinsk) and rename
  Asia/Aktau to Asia/Aqtau since `Aqtau' name seems to be the usual
  English rendering of the Kazakh name.

* Lebanon.

	Lebanon returned from DST to Standard Time on September 28,
	1996, instead of October 26 as previously announced.

  Shanks has Lebanon switching on May 1 and Oct 16 every year.
  Evidently that has changed more than once since 1991.  For lack of
  better info I'll propose a patch so that Lebanon switches on the
  last Sunday in March and the last Sunday in September, starting 1996.

* Libya

	if I'm right, the first actual time change was on September
	30, 1996, when clocks were set back an hour.

  That sounds right: since 1959, Libya has switched back and forth
  between straight UTC+2 and UTC+1 with DST.

* Mexico - the IATA and tz agree.

* Mongolia

  The IATA says that changes occur at local midnight, whereas Shanks
  says they occur at 02:00 standard time.  Also, the IATA says the
  fall transition is the 4th Friday (!) in October, whereas tz said it
  was the last Sunday in September.  I'll assume that the IATA is
  right, and that the rules changed in 1996, but we're undoubtedly
  missing some other changes between 1985 and 1995.

* Paraguay

	Paraguay will return from DST to Standard Time on March 1, 1997,
	instead of February 23 as previously announced.

  Shanks has this transition occuring on April 1.  For lack of better
  info, I'll assume they changed the rules from April 1 to March 1 in 1996.
* Portugal 

	Portugal (excluding Azores and Madeira) has switched from UTC+1 to UTC
	(both using DST).  There's no indication of when the change occurred.

  Martin Bruckmann <martin at> (1996-02-29) reported that the change
  occurred this spring, by Portugal not changing its clocks.

* Russia

  Russia's fall transition used to be the last Sunday in September,
  but it's changed to the last Sunday in October (at 02:00 standard
  time, as before).  Did the IATA catch this change?  Presumably this
  change also applies to Kazakhstan (I just checked the time
  server in Alma-Ata, and they're still on DST) as well as Kirgizstan.

  While we're on the subject, in the absence of any better info, the
  current tz database assumes that Belarus, Estonia, Latvia,
  Lithuania, and Moldova are moving their clocks on the last Sunday in
  October at 02:00 standard time, starting this year (in previous
  years they used September).  Since the EU, Russia, and Ukraine
  are all known to be making a similar switch, it wouldn't be surprising
  if the other countries are switching too; but we have no info.

* Sri Lanka

	Sri Lanka has changed from UTC+5:30 to UTC+6:30 year-round.  There's no
	indication of when the change occurred.

  It occurred 1996-05-25 00:00 local time, according to LankaWeb

* Ukraine

	Ukraine will begin and end DST at 3:00 am local time, rather than
	midnight as it used to.

  (The data make it clear that this is 3:00 local standard time.)  For
  most of Ukraine, this makes sense, since it's the EU rules.
  However, for Crimea, it doesn't make sense, since it's neither the
  EU rules (which operate at 4:00 local standard time) nor the Moscow
  rules (which operate at 2:00 local standard time).  Apparently the
  Ukrainians and the Crimeans are having a little tussle; there was a
  news story about this by Itar-Tass
  <URL:> at 09-18 00:43 entitled
  ``Crimea ponders over problem of time zone'' but unfortunately I
  don't have a copy of the story.  For now I'll assume Crimea was
  using Moscow rules until this year, and is as IATA reports afterwards.
  Shanks says all of Ukraine switches at 2:00 standard time, not midnight.
  For lack of better info I'll assume that this was true through 1995.

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