I have not found any single news item that any political decision has been taken whether to follow in Mexico the new US DST rule (that is a month longer than the old one). After the legal fight between former president Vicente Fox and former Mexico City mayor Manuel Lopez Obrador it was clarified in supreme court that DST issues remain with the Congress. On the page of the Energy Saving Trust of Mexico http://www.fide.org.mx/servicios/verano.html it says that DST (spanish: horario de verano) will start in 2007 Sunday 1.st. of April, and end Sunday 28.th. of October (old US-style DST). In the following page http://www.cenam.mx/HoraExacta.asp there is an explanation of that USA will change their schedule to be from Second Sunday of March at 2:00 until First Sunday of November at 2:00 while Mexico will continue with the old DST that is from First Sunday of April at 2:00 to Last Sunday of October at 2:00. However, I'm willing to bet a dinner on that Mexico will follow US from one of these two scenarios: (a) A hasty just-in-time decision puts Mexico on US DST just before 11.th. of March 2007. (b) Next year, a decision is made to put Mexico on the new US style DST, e.g. starting 9.th. of March 2008. Of course at the moment it looks like Mexico is in good company since Cuba, Haiti and Turks & Caicos Islands will also follow old-style US DST. But that is also a reason to keep a close eye on these countries, which might possibly change to keep it simpler to do business with the US (essentially the argument for Canada to change). I found the page http://www.cddhcu.gob.mx/bibliot/publica/inveyana/polisoc/horver/capitulo5.h tm which belongs to the Mexican Congrees (Camara de Diputados) that mentions the different timezone rules in Mexico since 1921. A fair amount of it corresponds well with the tz database (and therefore with Shanks, I presume) but there are differences. If everything is taken literally, there are at least a need to introduce new timezones for the states Campeche, Tamaulipas, Tabasco+CHS, Baja California Sur, Durango, Veracruz+Oaxaca, and Coahuila. Before I go too far with deciphering this, I would like to hear the general opinion about if this is an authoritative source or not - after all the Congress only recently got authority over timezone issues in Mexico (formally), and this list might have some goofed up details from extracting from old documents by "new" people. It does seem odd that there is no activity between 1948 and 1981. But perhaps we should just rely on Shanks for that period. Particularly I would like Paul Eggert's/David Olson's opinion on this. 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 shareware program World Time Explorer, I made: http://www.worldtimeexplorer.com/index.html