Daylight saving time in Mexico
Mexico adopted DST nationwide in 1996, even in its tropical regions, because of its increasing economic ties to the United States. Although the United States has changed the schedule for DST beginning in 2007, most of Mexico did not go along with it. Daylight saving time for Mexico begins the first Sunday of April, and ends last Sunday of October; and is usually referred to as the "Summer Schedule" (Horario de Verano).
In December 2009, Congress gave permission to ten northern border cities to synchronize their time to that of their US counterparts, resulting in these cities joining and leaving DST at the same time as the United States, relieving some border problems and confusion.
- Matamoros, Tamaulipas
- Reynosa, Tamaulipas
- Nuevo Laredo, Tamaulipas
- Anáhuac, Nuevo León
- Acuña, Coahuila
- Piedras Negras, Coahuila
- Ojinaga, Chihuahua
- Juárez, Chihuahua
- Mexicali, Baja California
- Tijuana, Baja California
The state of Baja California (not Baja California Sur) has observed daylight saving time from several decades ago and until 1996 was the only Mexican state to observe it. Since 2010 it has followed the extended schedule (beginning second Sunday of March, ending first Sunday of November) that has been used in the United States; this is mainly due to its close economic ties with the US state of California. Apart from the border cities (above), the rest of Mexico has continued to use the old USA / Canada DST schedule (beginning first Sunday of April, ending last Sunday of October).
The Marías Islands and the Revillagigedo Archipelago do not observe DST. The westernmost island of the Revillagigedo Archipelago, Clarion Island, uses UTC-8 (PST) all the time; thus, during DST, Mexico has 4 different time zones.
- Official web of the Electric Savings Fiduciary(Fideicomiso del Ahorro de Energia) of the Mexican Federal Electricity Commission 
- Daylight saving time by country