DAYLIGHT SAVINGS TIME TIME ZONE CHANGES ARE UPCOMING:

The pyramid clock of the snake god Kulkulkan in the temple city of Chichen Itza in Mexico is the world’s largest clock. The solstices and equinoxes are indicated by the shadows cast on its steps in relation to the position of the Sun:

Excerpted from URL: http://www.timeanddate.com/news/time/mexico-starts-dst-2010.html

Mexico One Hour Ahead on Easter, April 4, 2010

Most of Mexico will officially begin daylight saving time (DST) on Sunday, April 4, 2010, which is Easter Sunday. However, some of Mexico’s northern regions that border the United States will start DST at the same time as the United States and Canada.

The states of Sonora and Arizona do not observe DST, and remain on Mountain Standard Time (MST) all year round.

Mexico’s DST Schedule

Most of Mexico observes a daylight saving schedule that begins on the first Sunday of April, when the clocks move forward by one hour from 2 A.M. (02:00) to 3 A.M. (03:00) local time.  The DST schedule ends on the last Sunday of October, when the clocks move back from 2 A.M. (02:00) to 1 A.M. (01:00) local time.

Some areas in northern Mexico that border the United States follow a slightly different daylight saving schedule.  DST for these areas runs from the second Sunday of March until the first Sunday of November. This schedule applies to: Tijuana, Mexicali, Ciudad Juarez, Ojinaga, Ciudad Acuña, Piedras Negras, Anahuac, Nuevo Laredo, Reynosa, and Matamoros.

These areas follow the United States’ DST schedule as a way of maintaining strong business ties and economic relations between US/Mexico border cities and towns. Mexico’s Congress passed a law in December 2009 to ensure that the amended DST schedule for these areas would occur from 2010 onwards.  Sonora does not observe DST so the time does not change there.

I have been told that a modified Horario synchronized with the U.S. DST change will be observed in the entire State of Baja California, not just Tijuana and Mexicali, beginning March 14.  The Federal Congress has apparently approved this change thanks to a petition recently submitted by Sr. Gastón Luken, a Tijuana federal congressman.

I do not know the exact date the petition was approved.