Does Ciudad Juárez still change clocks?

Yes. Ciudad Juárez was exempted from the 2023 DST abolition. It follows the same DST schedule as the US: second Sunday in March clocks forward, first Sunday in November clocks back.

Is all of the country’s Mountain Time zone on the same time?

No. In summer, Ciudad Juárez is on MDT (UTC-6) while the rest of the Mountain Time areas are on MST (UTC-7). In winter, they match.

Why did Mexico keep DST on the border?

The law exempts ten border municipalities to maintain time alignment with their US neighbour cities. Without the exemption, El Paso and Juárez would be an hour apart for half the year, disrupting cross-border commuting, trade, and family life.

Does the Navajo Nation in Arizona also affect the Mountain Time Zone?

Yes, but it is a separate issue. The Navajo Nation, which extends into Arizona, observes DST even though Arizona does not. That creates a DST “doughnut” inside Arizona. The Hopi Reservation, surrounded by Navajo land, does not observe DST. This is unrelated to the 2022 law but adds complexity to the Mountain Time Zone’s internal consistency.

What IANA zone should I use for Juárez?

Use `America/Ciudad_Juarez`. For the rest of the country’s Mountain Time area, use `America/Ojinaga`. Do not use `America/Denver` for locations inside Mexico.

When do the clocks next change in Juárez?

In 2026, clocks go forward on 8 March at 02:00 local and back on 1 November at 02:00 local. In 2027, they go forward on 14 March and back on 7 November.

Mexico mountain time no dst

Mexico abolished daylight saving time in 2023, but one border city, Ciudad Juárez, kept it to stay in sync with El Paso, Texas. That creates a unique split inside the Mountain Time Zone.

A country killed DST, then carved out a border exception

Mexico’s federal government published the law ending daylight saving time on 30 October 2022. The clocks fell back one final time that same day. Since 2023, most of the country stays on standard time year-round.

The law makes an exception for ten municipalities that touch the US border. They can keep DST to stay aligned with their American neighbours. Ciudad Juárez is one of them.

Ciudad Juárez sits on the Rio Grande, directly across from El Paso, Texas. Both cities sit inside the Mountain Time Zone. Before the law, they changed clocks together. After the law, El Paso kept changing and Juárez would have stopped, putting the two cities an hour apart for half the year.

That would have been a disaster. Hundreds of thousands of people cross the border daily for work, school, shopping, and family. Twin cities split by a time zone boundary are hard enough. Twin cities that change their clocks on different days are unworkable.

So Juárez continues to observe DST on the US schedule. Second Sunday in March clocks go forward. First Sunday in November clocks go back.

What that means for the Mountain Time Zone

Before 2023, the Mountain Time Zone inside Mexico was simple. Every location in the zone used the same DST rules as the US and Canada. Now there are two regimes inside the country’s portion of the zone.

The IANA time zone database created a new zone for Juárez: America/Ciudad_Juarez. This zone follows exactly the same DST rules as America/Denver, the representative zone for the Mountain Time Zone in the US and Canada.

The rest of the country’s Mountain Time locations stay on America/Ojinaga, now fixed to UTC-7 year-round. That covers most of Chihuahua state, plus parts of Durango and Sonora that fall on the 105th meridian.

When you look at a clock in the nation’s Mountain Time Zone, you need to know which side of the border you are on.

Is Ciudad Juárez on the same clock as the rest of Mexico’s Mountain zone?

On 15 January 2026, every place in the Mountain Time Zone runs on Mountain Standard Time. Denver, Calgary, Phoenix, Juárez, and Ojinaga all read the same time. Phoenix stays on MST year-round because Arizona never observes DST, but on that January date it matches everyone else.

On 15 July 2026, everything changes. Denver is on Mountain Daylight Time (UTC-6). Calgary is on MDT. Juárez is on MDT. Phoenix is still on MST (UTC-7). And Ojinaga is also on MST, because it never changed its clocks in March.

The result: in summer, the Mountain Time Zone breaks into three groups.

Group 1: US states and Canadian provinces that observe DST. They run on MDT, UTC-6.
Group 2: Arizona and the country’s non-border areas. They run on MST, UTC-7.
Group 3: Ciudad Juárez. It runs on MDT, UTC-6, matching El Paso.

Group 2 and Group 3 are both inside the same country, 40 miles apart, and they read different times for half the year.

What Mexico’s split Mountain zone means for travelers and remote workers

Schedule a video call with someone in Chihuahua City in July and you need to know they are on MST, not MDT. Assume all of the nation’s Mountain Time zone is on the same clock and you will be an hour early or an hour late.

Fly from Denver to Juárez in July and your watch stays the same. Fly from Denver to Chihuahua City and you set it back an hour.

The same applies to software. If your application uses America/Ojinaga for a user in Chihuahua City and America/Denver for a user in Denver, the time difference is zero in January and one hour in July. That is correct behaviour. It surprises people who expect a single offset for an entire country.

Is Mexico’s Mountain Time split the same as Arizona’s DST exemption?

Arizona’s situation is similar but not identical. Arizona opted out of DST in 1968 and has stayed on MST year-round ever since. In summer, Arizona matches Pacific Daylight Time because both are UTC-7. Arizona is not on Pacific Time. It is on Mountain Standard Time, the same as Ojinaga.

The difference: Arizona’s choice is stable and well known. The border split is newer and less understood. The IANA database reflects it, but many consumer calendars and travel sites still treat the whole country as one time zone.

Which IANA zones cover Mexico mountain time no dst?

The metazone that CLDR calls America_Mountain includes these IANA zones:

America/Boise
America/Cambridge_Bay
America/Ciudad_Juarez
America/Dawson_Creek
America/Denver
America/Edmonton
America/Fort_Nelson
America/Inuvik
America/Phoenix

Every zone in this list except America/Phoenix and America/Ciudad_Juarez follows US DST rules. Phoenix stays on standard time. Juárez follows US DST rules but sits inside Mexico. The rest of the country’s Mountain Time zone uses America/Ojinaga, which is not in this metazone because it no longer observes DST.

How to handle Mexico mountain time no dst in practice

If you live in or travel to northern Mexico, know which side of the line you are on. Crossing between El Paso and Juárez? Do not change your watch. Travel south from Juárez to Chihuahua City in summer? You lose an hour.

If you build software that handles time zones, use the IANA zone identifiers. Do not hardcode offsets for the country. Do not assume the whole nation is on the same time. Use America/Ciudad_Juarez for Juárez and America/Ojinaga for the rest of the Mountain Time area. Let the database handle the DST transitions.

For a complete list of cities that share the Mountain Time metazone, see the cities on mountain standard time page. For the exact dates of the spring and fall clock changes, see the DST dates page.