Mexico City's clocks do not move. Since October 2022, when the national Senate abolished daylight saving time, the capital has been locked on Central Standard Time (UTC-6) every day of the year. That single decision split the Central Time zone into two realities: a permanent standard-time interior and a northern border strip that still springs forward with the United States.

The 2022 Abolition

Mexico's Senate voted in October 2022 to eliminate seasonal clock changes nationwide. The law took effect for the 2023 calendar year. Roughly 95 percent of the Mexican population stopped changing clocks.

The abolition did not create a new time zone. Mexico returned to permanent standard time. In the central region that means fixed UTC-6. The Pacific zone sits at UTC-7, and Baja California at UTC-8. Lawmakers framed the change as a health and safety measure, citing studies that linked DST to sleep disruption and cardiovascular problems. Public support for clock changes had dropped sharply since DST was introduced in 1996.

Mexico City: Fixed UTC-6, All Year

Mexico City, population 12,294,193, operates on a fixed UTC-6 offset. The IANA time zone database lists it as America/Mexico_City. There is no seasonal adjustment.

Same Clock as Chicago, But Only in Winter

Mexico City and Chicago share the same local time from early November through early March. When Chicago and Dallas spring forward to Central Daylight Time (UTC-5) on the second Sunday of March, Mexico City stays put. The two cities then sit one hour apart for roughly eight months.

Daylight Hours Without the Jump

Without a spring-forward jump, Mexico City's daylight hours shift gradually. On the March equinox (20 March 2026), sunrise is at 06:41 and sunset at 18:47, giving 12 hours 6 minutes of daylight. By the June solstice (21 June 2026), sunrise moves to 05:58 and sunset stretches to 19:16: 13 hours 18 minutes of daylight. The September equinox (22 September 2026) brings sunrise at 06:24 and sunset at 18:33. On the December solstice (21 December 2026), sunrise is at 07:05 and sunset at 18:03, with just 10 hours 57 minutes of daylight. No clock change interrupts the curve.

What the Fixed Offset Means for Daily Life

Office hours, school schedules, and meal times stay consistent. Lunch still peaks at noon. Dinner runs 6:00 to 8:00 p.m. The city avoids the documented spring-forward spike in traffic accidents and workplace injuries that hits U.S. cities in March.

The Border Exception

Mexico's DST abolition included a carve-out: municipalities within 20 kilometers of the U.S. border may continue observing daylight saving time. The exception prevents economic disruption in communities where cross-border commuting, trade, and daily life are tightly integrated.

Matamoros and Ojinaga

Matamoros, across the Rio Grande from Brownsville, Texas, uses the IANA zone America/Matamoros. It follows the U.S. DST schedule exactly: clocks go forward on the second Sunday of March and back on the first Sunday of November. Ojinaga uses America/Ojinaga and aligns with the Mountain Time zone's DST pattern.

Ciudad Juárez

Ciudad Juárez, across from El Paso, Texas, also observes DST. Both cities sit in the Mountain Time zone and share the same clock year-round.

Why Border Cities Stay in Sync

A Matamoros resident who crosses into Brownsville for work each morning would face a one-hour mismatch without the exception. The same logic applies to school schedules, medical appointments, and retail hours. The border zone follows U.S. DST; the rest of Mexico does not.

US-Mexico Business and Travel

The DST split creates a scheduling variable for anyone working across the border. During winter months, Mexico City and the Windy City are both on UTC-6. A 10 a.m. meeting works for both sides. From March through November, Mexico City is one hour behind: a 10 a.m. call in Chicago is 9 a.m. in the Mexican capital.

Border Cities Stay Simple

For Matamoros and Brownsville, there is no complication. Both follow U.S. DST. A meeting between the two always happens at the same local time. Ciudad Juárez and El Paso work the same way.

The Mexican Stock Exchange

The Bolsa Mexicana de Valores (BMV) operates on Mexico City time, fixed at UTC-6 year-round. For traders in Chicago, the BMV opens at 8:30 a.m. local time in winter but 9:30 a.m. in summer. That one-hour shift affects early morning trading strategies during U.S. daylight saving months.

Cross-Border Calling Windows

The best window for calls between the U.S. interior and Mexico City narrows in summer. From November to March, 9:00 a.m. to 4:00 p.m. CT works for both. From March to November, shift U.S. calls one hour later, or Mexican calls one hour earlier. Border cities need no adjustment.

Mexico City vs Chicago: Same in Winter, Apart in Summer

From early November to early March, both cities sit on UTC-6. A phone call requires no time zone math. From the second Sunday in March to the first Sunday in November, Mexico City stays on CST while Chicago moves to CDT (UTC-5). The gap is one hour.

This is the reverse of the pre-2022 arrangement, when both cities observed DST on the same schedule. Anyone scheduling recurring calls between the two must now add an hour to Chicago time during U.S. daylight saving months.

The same pattern applies to other Mexican cities in the central zone. Guadalajara, Puebla, León de los Aldama, and Santiago de Querétaro are all fixed at UTC-6 year-round. Their U.S. counterparts in Houston, Dallas, and San Antonio shift seasonally.

Other Central Time Cities in Mexico

Mexico's Central Time zone holds some of the country's largest population centers, all on permanent standard time.

Mexico City and Its Boroughs

Mexico City proper counts 12,294,193 residents. Iztapalapa adds 1,835,486 and Gustavo Adolfo Madero contributes 1,185,772. All three use America/Mexico_City and stay on UTC-6.

The Bajío and Central Highlands

León de los Aldama (1,579,803), Santiago de Querétaro (1,594,212), and Puebla (1,692,181) all sit on fixed UTC-6. Ecatepec de Morelos, with 1,645,352 people, does the same.

Guadalajara and Zapopan

Guadalajara (1,385,629) and Zapopan (1,476,491) share the America/Mexico_City zone. Their clocks never change.

Monterrey and Mérida

Monterrey (1,135,512) uses America/Monterrey and stays on standard time. Mérida (1,201,000) uses America/Merida. Neither observes DST. Both are one hour behind their U.S. counterparts during the long summer months.

The Ley del Sistema Horario

Mexico's time zone rules are codified in the Ley del Sistema Horario, amended in October 2022. The law designates three standard time zones: UTC-8 for Baja California, UTC-7 for Sonora and most of the Pacific coast, and UTC-6 for the central region including Mexico City.

The border exception is written directly into the law. Municipalities within 20 kilometers of the U.S. border may observe DST. The law also grants the Mexican government authority to adjust time zones in response to international agreements or economic needs. No such changes are currently pending.

For anyone crossing the border, the rule is straightforward. Check whether the Mexican city is a border municipality. If it is, it follows U.S. DST. If it is not, the clock stays on standard time, every day of the year.