Daylight saving time in Mexico

Mexico adopted daylight saving time (Spanish: horario de verano) 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, only the municipalities located less than 20 km from the border have adopted the change. 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). Add one hour.

In December 2009, Congress gave permission to the municipalities located less than 20 kilometers from the US border to synchronize their time to that of their US counterparts, resulting in these municipalities joining and leaving DST at the same time as the United States, relieving some border problems and confusion.

Apart from the border municipalities (above), daylight saving time for Mexico begins the first Sunday of April, and ends last Sunday of October.

A bill was proposed by Rep. Francisco Saracho (PRI) in September 2015 to reduce confusion by modifying the aforementioned DST start and end dates, observed by the rest of the country, to match those observed by the border municipalities (above). The bill was discarded by congress on June 29, 2016.

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.

The state of Sonora has not observed DST since 1998 because of the non-observance of DST by its neighbor Arizona and its important economic ties with that US state.

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.

The state of Quintana Roo has decided to not observe DST from February 1, 2015. At the same time, they are switching timezone from CST to EST.

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