Mexico Central Time: key details

A 9:00 AM meeting in Mexico City is a 9:00 AM meeting in Chicago from November through March. From March through November, that same 9:00 AM Mexico City meeting happens at 10:00 AM in Chicago. The reason is simple: Mexico stopped changing its clocks in 2022. The United States did not.

The 2022 abolition

Mexico adopted time zones in 1921, with Mexico City on the Central zone. For decades, the country observed daylight saving time nationally, roughly matching US DST dates. That ended on 30 October 2022.

The Mexican Congress voted to abolish seasonal clock changes for most of the country. The law took effect on the same day Mexico would normally have fallen back. Instead, clocks stayed put. Most of Mexico now sits permanently on standard time.

Energy savings were minimal. Health experts pointed to disrupted circadian rhythms. Public support for abolition was strong.

But the abolition was not total. Baja California and several border municipalities kept DST because they are economically tied to US border cities. If Tijuana and San Diego ran on different clocks, cross-border business, healthcare, and family visits would all suffer.

Mexico City: UTC-6 year-round

Mexico City is the anchor of Mexico's Central zone. Its IANA time zone is America/Mexico_City, and its offset is UTC-6. Always. No exceptions.

That means the local time never changes, regardless of what the US does. The sun shifts. On the June solstice, sunrise hits at 05:58 and sunset at 19:16, giving 13 hours and 18 minutes of daylight. On the December solstice, sunrise comes at 07:05 and sunset at 18:03, just 10 hours and 57 minutes of daylight. The clock stays fixed through all of it.

Chicago (America/Chicago) runs UTC-6 during US standard time and UTC-5 during US daylight time. So the two cities are identical during winter months and differ by one hour during US summer.

Border municipalities: the cities that still change

Not all of Mexico is on permanent CST. The border exception is written into the 2022 law.

Baja California continues to observe DST, aligning with California. A handful of municipalities along the northern border also keep seasonal changes, including Ciudad Juárez (across from El Paso) and Nuevo Laredo (across from Laredo).

These areas follow US DST dates. When the US springs forward in March, they spring forward. When the US falls back in November, they fall back. Cross-border communities stay synchronized.

The result is a patchwork: most of Mexico is permanent UTC-6, but the border region shifts with US time. Scheduling a call between El Paso and Chihuahua City requires checking which season it is.

Scheduling across the border

The Mexico-US scheduling landscape changed dramatically in 2022. Before then, both countries followed similar DST calendars. Mexico City and Chicago stayed in sync year-round. Now they diverge for roughly seven months.

November to March (US standard time): - Mexico City: UTC-6 - Chicago: UTC-6 - Same time. No conversion needed.

March to November (US daylight time): - Mexico City: UTC-6 - Chicago: UTC-5 (CDT) - Mexico City is one hour behind Chicago.

A "9 AM CT" meeting invite needs different handling depending on the month. During US summer, 9 AM in Chicago is 8 AM in Mexico City. During US winter, it is 9 AM in both.

The same logic applies to other US cities. Houston, Dallas, and San Antonio all follow the Chicago pattern. New York is one hour ahead of Mexico City during US DST and two hours ahead during US standard time.

Mexico time zone history

Mexico adopted standard time zones in 1921, following the railroad-driven model the US had used since 1883. Mexico City landed on the Central zone, aligned with Chicago and Dallas.

For most of the 20th century, Mexico observed DST sporadically. The modern era of consistent DST began in 1996, when Mexico aligned its schedule with the US to ease cross-border trade and travel. That alignment lasted 26 years. The 2022 abolition broke it.

Now, Mexico's time zones are simpler in some ways and more complicated in others. Most of the country is permanent UTC-6 (Central), UTC-7 (Mountain), or UTC-8 (Pacific). Baja California and border municipalities add DST into the mix. The system is predictable if you know the rules and genuinely confusing if you assume Mexico follows the US.

Mexico City and Chicago across the year

January: - Mexico City: UTC-6 - Chicago: UTC-6 (CST) - Same time.

July: - Mexico City: UTC-6 - Chicago: UTC-5 (CDT) - Mexico City is one hour behind.

November (after US fall-back): - Mexico City: UTC-6 - Chicago: UTC-6 (CST) - Same time again.

The entire rule: the two cities are identical during US standard time. Mexico City runs one hour behind during US daylight time.

For broadcasters, this matters. A primetime show airing at 8 PM in Mexico City airs at 9 PM in Chicago during US summer and at 8 PM during US winter. Sports schedules, live events, and news programs all shift.

For healthcare workers scheduling telehealth appointments, the same rule applies. A 2 PM appointment in Mexico City is 2 PM in Chicago during winter and 3 PM during summer. Missed connections happen when people forget which season it is.

The "CST" confusion

The abbreviation CST is overloaded.

  • Central Standard Time (UTC-6): Used by Chicago, Mexico City, and most of the US Central zone during standard time.
  • China Standard Time (UTC+8): All of China runs on this single zone.
  • Cuba Standard Time (UTC-5): Cuba uses this offset, with DST to UTC-4.

Context matters. "CST" can mean three different things.

For Mexico specifically, there is an additional problem. Mexico City is on CST year-round now, but many US-based converters still assume Mexico follows US DST. A tool that does not know about the 2022 abolition will give the wrong time during US summer months.

Check whether the converter uses IANA time zone data (America/Mexico_City) or a fixed offset. Modern tools handle this correctly. Older ones may not.

Daily life in Mexico's Central zone

Mexico's permanent standard time reshapes the daily rhythm. Business hours typically run 9:00 AM to 6:00 PM, with a one- to two-hour lunch break. The main meal, comida, happens between 2:00 PM and 4:00 PM. It is the central social meal of the day. A lighter evening meal, cena, runs from 8:00 PM to 10:00 PM.

Banks operate 9:00 AM to 4:00 PM on weekdays, with some Saturday morning hours. Government offices run 9:00 AM to 3:00 PM or 9:00 AM to 5:00 PM. Schools often run a morning shift from 7:00 AM to 1:00 PM and an afternoon shift from 1:30 PM to 7:30 PM in some areas. Shops and mercados open around 9:00 AM and close by 8:00 PM; mercados often shut by 6:00 PM.

Compare this to the US Central zone. Breakfast there runs 6:30 AM to 8:30 AM, lunch 11:30 AM to 1:00 PM, and dinner 5:30 PM to 7:30 PM. The US day starts and ends earlier. Cross-border calls work best in the late morning, when both countries are fully operational.

Best calling windows

Mexico City to Europe: 7:00 AM to 12:00 PM Mexico City time (1:00 PM to 6:00 PM in London or Paris).

Mexico City to India: 7:00 AM to 8:30 AM Mexico City time (6:00 PM to 7:30 PM IST) or 7:00 PM to 9:00 PM Mexico City time (6:30 AM to 8:30 AM IST).

Mexico City to Japan: 6:00 AM to 8:00 AM Mexico City time (8:00 PM to 10:00 PM Tokyo) or 6:00 PM to 8:00 PM Mexico City time (9:00 AM to 11:00 AM Tokyo).

Mexico City to Sydney: 4:00 PM to 6:00 PM Mexico City time (8:00 AM to 10:00 AM Sydney the next day) or 6:00 AM to 8:00 AM Mexico City time (10:00 PM to midnight Sydney).

The bottom line

Mexico abolished DST in October 2022. Mexico City and most of the country now run on permanent Central Standard Time (UTC-6) year-round. Border municipalities near the US still observe DST to stay aligned with their northern neighbours.

The rule for cross-border scheduling: Mexico City and Chicago match during US standard time. Mexico City is one hour behind during US daylight time. That is it.

The era of coordinated clock changes between the US and Mexico is over.