America/Mexico_City

TZ identifier and aliases

America/Mexico_City is the canonical identifier for Central Time in Mexico, covering the capital and most of the country's interior. Mexico/General is an older name still pointing at the same rules but is a deprecated alias — use America/Mexico_City in new code. America/Monterrey, America/Merida, America/Chihuahua and America/Bahia_Banderas currently share identical rules and are folded into the same entry.

UTC offset and DST rule

America/Mexico_City is -06:00 year-round with no daylight saving time. Mexico's Congress discontinued DST nationally in a law published in November 2022 — the most significant change to Mexican timekeeping in decades — so most of the country, including Mexico City, no longer shifts clocks at all. The main exceptions are Baja California and a strip of municipalities within 20km of the US border, which still follow the US DST schedule to stay aligned with neighboring American states; Sonora, notably, does not observe DST and hasn't for years.

Using it in cron, CI and Postgres

Set TZ=America/Mexico_City for a process that should schedule by central Mexican local time — naming the zone rather than a fixed -06:00 offset keeps a config correct automatically if the rule changes again, which is a real possibility for a zone with such a recent legal shift. Postgres accepts it via SET TIME ZONE 'America/Mexico_City'; or the timezone setting. Because the zone is currently fixed, a cron job's local-time schedule now behaves identically every day of the year for most of the country — a change worth double-checking in any system that still has DST-adjustment logic left over from before the 2022 law, since that code is now either dead or, if mistakenly still active, quietly wrong.

History and quirks

Mexico had observed some form of daylight saving since 1996, but public opposition grew over the following decades — polling consistently showed a majority of Mexicans wanted it abolished, citing disrupted sleep and routines for limited measurable energy savings. Congress acted on that sentiment in October 2022, discontinuing DST nationwide except along the US border, where keeping the same clock as neighboring US states matters more for daily cross-border commuting and commerce than any national energy policy. The exception itself is a good illustration of how time zone rules often follow economic geography rather than political borders: Baja California's tourism and labor markets are tightly linked to California's, so it kept US-style DST even as the rest of the country dropped it entirely.

Offsets and DST transitions on this page are computed from the IANA time zone database bundled with your browser; the rules described above were verified against tzdata 2026b when this page was published.