Mexico simplified its timezone system in October 2022 when the federal government abolished daylight saving time for most of the country. The majority of Mexico now stays on Central Standard Time (CST, UTC−6) year-round — including Mexico City, Guadalajara, Monterrey, and the southeast.
The northwestern border zone (Baja California — Tijuana, Mexicali, Ensenada) continues to observe Pacific Time (UTC−8 standard / UTC−7 daylight) aligned with California, to maintain continuity with the adjacent US market. DST in Baja California: forward on the US schedule (2nd Sunday in March, 1st Sunday in November).
The states of Sonora and most of northern/western Mexico use Mountain Standard Time (MST, UTC−7) year-round with no DST. Sonora deliberately aligns with Arizona for cross-border commerce.
Key gaps from Mexico City (CST, UTC−6): New York (EST) is 1 hour ahead. Los Angeles (PST) is 2 hours behind. London (GMT) is 6 hours ahead in winter. Chicago shares the same standard time offset as Mexico City.