<P> 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 . </P> <P> 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 . </P>

When did daylight savings time start in mexico