Mexico has enacted a new law governing how time zones will be treated throughout the country. On October 28, 2022, the Decree issuing the Time Zone Law in the United Mexican States (the "Law") was published in the Official Journal of the Federation. The new Law became effective October 30, 2022 and, with it, the previous Law of the Time System in the United Mexican States was repealed, as was the Decree establishing the seasonal time schedule applied in the United Mexican States.
This new Law is mandatory throughout Mexico and acknowledges the application and validity of four different time zones within Mexican territory, as well as the hours that correspond according to their location.
For the purposes of the Law, the following time zones and their corresponding meridians were established: (1) Central Zone, corresponding to the meridian 90 degrees West of Greenwich and comprising most of the Mexican territory; (2) Pacific Zone, referring to the meridian 105 degrees West of Greenwich and comprising the states of Baja California Sur, Nayarit (except for the municipality of Bahía de Banderas, which corresponds to the Central Zone), Sinaloa, and Sonora; (3) Northwest Zone, referring to the meridian 120 degrees West of Greenwich and comprising the state of Baja California; (4) Southeast Zone, referring to the meridian 75 degrees West of Greenwich and comprising the state of Quintana Roo; and (5) the islands, reefs and keys are included within the meridian to which their geographical location corresponds and in accordance with accepted international legal treaties and agreements.
The Law provides that in Mexico a standard time schedule is established according to the zones described in the prior paragraph, and that a seasonal time schedule will apply only to certain states and municipalities of the Northern border in accordance with the following rules: (a) for the border municipalities of Coahuila (also including the municipalities of Allende, Morelos and Villa Unión), Nuevo León and Tamaulipas, the meridian 75 degrees West of Greenwich will be applied; and (b) for the state of Baja California, the meridian 105 degrees West of Greenwich will be applied. Said border seasonal time schedule will take effect from 2 a.m. on the second Sunday in March and will end at 2 a.m. on the first Sunday in November.
Likewise, the Law specifies certain mechanisms so that a state, through its legislature, may request to modify the time zones or seasonal time schedules in the state or its municipalities by sending an initiative to the federal Congress for its consideration and voting, subject to the opinion of the Ministry of the Interior. In this case, upon a proposal by the majority of the state legislature or the Governor of the respective state, forums and/or citizen consultations will be held to understand the public’s opinion on the matter.
This new Law represents a challenge for the border areas in the North of the country, especially with respect to the application of seasonal time schedules, since during their application these areas will be subject to a different time schedule with respect to states or municipalities with which they have historically shared the same time schedule. This issue is especially relevant for border municipalities in Sonora and Chihuahua, since the Law does not contemplate a seasonal time schedule for them, unlike the rest of the municipalities along the Northern border of Mexico.
On the other hand, there is some concern about the possible negative effects that the elimination of the summer time schedule could have after 26 years being of applied in Mexico,, including for example, increases in the consumption of electrical energy, logistical confusion, or increases in crime during night hours. It is hoped that Mexican legislators have duly studied and considered these concerns.