There are four time zones in Mexico. Most of the country uses Central Standard Time, which is officially named Zona Centro or Central Zone. The state of Quintana Roo (Cancún and the Riviera Maya) uses Eastern Standard Time. Officially, it is called Zona Sureste or Southeast Zone. The states of Chihuahua, Nayarit, Sonora, Sinaloa and Baja California Sur use Mountain Standard Time, called Zona Pacífico or Pacific Zone (except for the cities on or near the Bay of Banderas that are on Central Standard Time). Baja California Norte uses Pacific Standard Time, which is called Zona Noroeste or Northwest Zone.
All island territories including reefs and keys observe the time zone based upon the longitude of their location.
Daylight Saving Time begins at 2:00 a.m. local time on the first Sunday in April and falls back to Standard Time at 2:00 a.m. on the last Sunday in October. The states of Sonora and Quintana Roo do not observe Daylight Saving Time.