Traditionally, Daylight Saving Time starts the first Sunday in April and ends the last Sunday in October. Mexico follows the tradition dates, whereas the United States has revised the dates so that starting in 2007 Daylight Saving Time begins the second Sunday in March and ends first Sunday in November.
This has caused confusion for many living in the US-Mexico border area. Beginning in 2010 Mexican border cities will follow the United States Daylight Saving Time schedule, as explained in the article cited below.
U.S.-Mexico Border Cities On Same Time In 2010
By Amy Isackson
December 30, 2009
A new Mexican law means less scheduling snafus this spring for people who cross the border between Tijuana and San Diego. The new law synchronizes daylight savings schedules in U.S. and Mexican border cities in 2010.
Since 2007, different daylight savings time schedules have caused an hour gap between US Mexico border cities for a few weeks every spring and fall.
In March 2007, the US and Canada switched to a new daylight savings schedule to save energy, but Mexico did not.
Gaston Luken, the Tijuana congressman who sponsored the bill to synchronize the clocks, says the benefits are multi-fold, "We'll save energy because we'll take more advaneforum.xxxe of the sun. There are savings in terms of transactional costs along the border, for commerce, for industry, for maquila, for tourism."
Synchronizing clocks will also save tens of thousands of people from choreographing their schedules to compensate for the hour gap.
The measure faced little opposition in Mexico's Congress, but Luken says it highlighted the disconnect between border cities and Capitol lawmakers. He says there was little awareness of the problem in Mexico City.
http://www.kpbs.org/news/2009/dec/30/us-mexico-border-cities-same-time-2010/