I have found an application of the rule EUAsia for Azerbaijan, which results in DST for Azerbaijan since 01-Jan-1996 which doesn't seem logical, and does not follow common sense. I don't have a version of zdump here, but use JodaTime, a package that uses tz database directly to produce the tz transitions. Jodatime reports the following transitions for Baku for 1996: UTC: 1995-12-31T19:59:59.000Z, Asia/Baku: 1995-12-31T23:59:59.000+04:00 UTC: 1995-12-31T20:00:00.000Z, Asia/Baku: 1996-01-01T01:00:00.000+05:00 UTC: 1996-10-27T00:59:59.000Z, Asia/Baku: 1996-10-27T05:59:59.000+05:00 UTC: 1996-10-27T01:00:00.000Z, Asia/Baku: 1996-10-27T05:00:00.000+04:00 This is based on the following tz database definition: Zone Asia/Baku 3:19:24 - LMT 1924 May 2 3:00 - BAKT 1957 Mar # Baku Time 4:00 RussiaAsia BAK%sT 1991 Mar 31 2:00s 3:00 1:00 BAKST 1991 Aug 30 # independence 3:00 RussiaAsia AZ%sT 1992 Sep lastSat 23:00 4:00 - AZT 1996 # Azerbaijan time 4:00 EUAsia AZ%sT 1997 4:00 Azer AZ%sT The EUAsia rule looks like this: # These rules are stolen from the `europe' file. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule EUAsia 1981 max - Mar lastSun 1:00u 1:00 S Rule EUAsia 1996 max - Oct lastSun 1:00u 0 - As you can see above, the intention was simply to copy EU rules to the 'asia' file so as to use the same logic (because the asia file can't see the europe file). However, the above implementation is a cut-down version of EU rule, where the logic is presumably that we only need rules for 1996 and beyond. This has the side effect that DST in the EUAsia rule is applied Last Sunday of March 1981 and maintained unaltered until Last Sunday of October 1996. The error is that DST was (probably) not observed from 01-Jan-1996 to Last Sunday of March 1996, although I don't have authoritative information about this. I therefore suggest the following change: # These rules are stolen from the `europe' file. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule EUAsia 1981 max - Mar lastSun 1:00u 1:00 S +Rule EUAsia 1979 1995 - Sep lastSun 1:00u 0 - Rule EUAsia 1996 max - Oct lastSun 1:00u 0 - This will give EUAsia rule the expected behavior right from 1981, with DST transitions equivalent to the EU rule. Regards, Jesper Jesper Nørgaard Welen Email: jnorgard@Prodigy.Net.mx Project Leader (Líder de Proyecto) Software CIMMYT - Centro Internacional de Mejoramiento de Maíz y Trigo Dirección: CIMMYT Int. c/o Jesper Nørgaard Km. 45, Carretera México-Veracruz El Batán Texcoco, Edo. de México CP 56130 MEXICO Tel.: +52 (55) 58-04-20-04 ext. 1374 Fax: +52 (55) 58-04-75-58 Tel. Casa: 53-10-05-95 ó 53-10-97-78 Download the free program World Time Explorer, I made: http://www.cimmyt.org/timezone/index.htm