Mountain Time Zone Map

Mountain Time is UTC−7 standard (MST) and UTC−6 in summer (MDT). It covers Colorado, Utah, Wyoming, Montana, New Mexico, and Arizona (which skips daylight saving), plus southern Idaho and the western parts of Kansas, Nebraska, the Dakotas, eastern Oregon, and far-west Texas (El Paso).

Mountain Time · Denver12:08 PMMST / MDT · UTC−7 / UTC−6

Your time11:38 PMSAT, OCT 31UTC+5:30

Pacific timePacific11:08 AMSAT, OCT 31UTC-7

Mountain timeMountain12:08 PMSAT, OCT 31UTC-6

Central timeCentral1:08 PMSAT, OCT 31UTC-5

Eastern timeEastern2:08 PMSAT, OCT 31UTC-4

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Pacific Mountain Central Eastern Alaska HawaiiHatched: no daylight saving

Daylight saving in 2026

Mountain Time moves from UTC−7 to UTC−6 for the summer. Arizona (except the Navajo Nation) stays on Mountain Standard Time year-round, so in summer it matches Pacific.

Comparing a meeting across zones? The time converter applies each zone’s rules for the date you pick.

March 8clocks go forward an hour at 2 a.m.November 1clocks go back an hour at 2 a.m.

Live clocks in Mountain Time

Denver, COMountain Time · UTC-612:08 PM
Phoenix, AZMountain Time (no DST) · UTC-711:08 AM

States in this zone

How the zones came to be

Five dates behind every clock on this page, from sundials to daylight saving.

Before 1883

Sun time

Every town set its clocks by the sun overhead, so noon in Boston came about twelve minutes before noon in New York, and railroads juggled dozens of local times.

A weathered stone sundial with Roman numerals and an iron gnomon — A sundial on the porch of St Giles’ Church, Chesterton, England.

November 18, 1883

Railroad time

U.S. and Canadian railroads switched to standard zones an hour apart, set from Greenwich. Many towns reset their clocks the same day, remembered as “the day of two noons.”

A gold railroad pocket watch with a white dial, lying on its chain — A railroad pocket watch made for the Plant System, a railroad of the Southeast.

1884

Greenwich

Delegates at the International Meridian Conference in Washington chose the Greenwich meridian as longitude zero — the line every UTC offset on this site is counted from.

A red time ball on its mast above the octagonal turret of the Royal Observatory — The time ball on the Royal Observatory, Greenwich, dropped at 1 p.m. as a public time signal since 1833.

1918 and 1966

Time by law

The Standard Time Act made the zones federal law in 1918. The Uniform Time Act of 1966 set common daylight-saving rules and let a state opt out, as Arizona and Hawaii do.

The open back of a railroad-grade pocket watch, showing its jewelled movement — The movement of a Hamilton railroad-grade pocket watch, about 1929.

2026

Daylight saving

Since 2007 clocks spring forward on the second Sunday of March and fall back on the first Sunday of November: March 8 and November 1 this year.

A large 24-hour clock face set into a red brick wall beneath a sign reading Royal Observatory Greenwich — The Shepherd Gate Clock at Greenwich, which shows Greenwich Mean Time on a 24-hour dial.

Frequently asked questions

Does Arizona observe Mountain Daylight Time?

No — Arizona stays on MST year-round. The Navajo Nation, which is inside Arizona, does observe MDT, so that part of the state jumps ahead in summer.

Which states use Mountain Time?

Colorado, Utah, Wyoming, Montana, New Mexico, and Arizona are entirely on Mountain Time. Idaho (south), Kansas (four western counties), Nebraska (the west), North Dakota (the southwest), South Dakota (the west), Oregon (most of Malheur County), and Texas (El Paso and Hudspeth counties) are partly Mountain.

Is El Paso on Mountain or Central Time?

Mountain Time. El Paso and Hudspeth counties are the only part of Texas on Mountain Time; the rest of the state is Central.

Sources: zone boundaries from the U.S. Department of Transportation’s time zone regulations (49 CFR Part 71); offsets and daylight saving rules from the IANA time zone database. See Data Sources for how this site uses them.