The Mountain Time Zone of North America keeps time by subtracting seven hours from

Coordinated Universal Time Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. It is within about one second of mean solar time (such as UT1) at 0° longitude (at the IERS Reference Meridian as the currently ...

(UTC) when standard time ( UTC−07:00) is in effect, and by subtracting six hours during

daylight saving time Daylight saving time (DST), also referred to as daylight savings time or simply daylight time (United States, Canada, and Australia), and summer time (United Kingdom, European Union, and others), is the practice of advancing clocks (typical ...

( UTC−06:00). The clock time in this zone is based on the mean solar time at the

105th meridian west The meridian 105° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, North America, the Pacific Ocean, the Southern Ocean, and Antarctica to the South Pole. The 105th meridian west forms a gre ...

of the Greenwich Observatory. In the United States, the exact specification for the location of

time zone A time zone is an area which observes a uniform standard time for legal, commercial and social purposes. Time zones tend to follow the boundaries between countries and their subdivisions instead of strictly following longitude, because i ...

s and the dividing lines between zones is set forth in the

Code of Federal Regulations In the law of the United States, the ''Code of Federal Regulations'' (''CFR'') is the codification of the general and permanent regulations promulgated by the executive departments and agencies of the federal government of the United States. ...

at 49 CFR 71. In the United States and Canada, this time zone is generically called Mountain Time (MT). Specifically, it is Mountain Standard Time (MST) when observing standard time, and Mountain Daylight Time (MDT) when observing daylight saving time. The term refers to the Rocky Mountains, which range from

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost Provinces and territories of Canada, province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include ...

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe, New Mexico, Santa Fe , LargestCity = Albuquerque, New Mexico, Albuquerque , LargestMetro = Albuquerque metropolitan area, Tiguex , Offi ...

. In Mexico, this time zone is known as the or ("Pacific Zone"). In the US and Canada, the Mountain Time Zone is to the east of the Pacific Time Zone and to the west of the

Central Time Zone The North American Central Time Zone (CT) is a time zone in parts of Canada, the United States, Mexico, Central America, some Caribbean Islands, and part of the Eastern Pacific Ocean. Central Standard Time (CST) is six hours behind Coordina ...

. In some areas, starting in 2007, the local time changes from MST to MDT at 2am MST to 3am MDT on the second Sunday in March and returns at 2am MDT to 1am MST on the first Sunday in November.

Sonora Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Federal Entities of Mexico. The state is divided into 72 municipalities; the ...

in Mexico and most of

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a U.S. state, state in the Southwestern United States. It is the list of U.S. states and territories by area, 6th largest and the list of U.S. states and territories by population, 14 ...

in the United States do not observe daylight saving time, and during the spring, summer, and autumn months they are on the same time as Pacific Daylight Time. The Navajo Nation, most of which lies within Arizona but extends into Utah and New Mexico (which do observe DST), does observe DST, although the Hopi Reservation, as well as some Arizona state offices lying within the Navajo Nation, do not. The largest city in the Mountain Time Zone is

Phoenix, Arizona Phoenix ( ; nv, Hoozdo; es, Fénix or , yuf-x-wal, Banyà:nyuwá) is the capital and most populous city of the U.S. state of Arizona, with 1,608,139 residents as of 2020. It is the fifth-most populous city in the United States, and the o ...

; the Phoenix metropolitan area is the largest metropolitan area in the zone.

Canada

One province and one territory are fully contained in the Mountain Time Zone: *

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...

* Yukon (no DST) On September 24, 2020, Yukon switched to the Mountain Standard Time year-round. Therefore, clocks in Yukon and Alberta are the same in the winter, and Alberta is one hour ahead in summer. Previously the territory had used the Pacific Time Zone with daylight saving time: UTC−8 in winter and UTC−7 in summer. One province and one territory are split between the Mountain Time Zone and the Pacific Time Zone: *

– northeastern and southeastern regions *

Northwest Territories The Northwest Territories (abbreviated ''NT'' or ''NWT''; french: Territoires du Nord-Ouest, formerly ''North-Western Territory'' and ''North-West Territories'' and namely shortened as ''Northwest Territory'') is a federal territory of Canada. ...

– Tungsten One territory and one province are split between the Mountain Time Zone and the

Nunavut Nunavut ( , ; iu, ᓄᓇᕗᑦ , ; ) is the largest and northernmost territory of Canada. It was separated officially from the Northwest Territories on April 1, 1999, via the '' Nunavut Act'' and the '' Nunavut Land Claims Agreement Act'' ...

: Kitikmeot Region *

Saskatchewan Saskatchewan ( ; ) is a province in western Canada, bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and on the south by the U.S. states of Montana and North ...

Lloydminster Lloydminster is a city in Canada which has the unusual geographic distinction of straddling the provincial border between Alberta and Saskatchewan. The city is incorporated by both provinces as a single city with a single municipal administrat ...

and vicinity

Mexico

The following states have the same time as Mountain Time Zone: :* Baja California Sur :*

Nayarit Nayarit (), officially the Free and Sovereign State of Nayarit ( es, Estado Libre y Soberano de Nayarit), is one of the 31 states that, along with Mexico City, comprise the Federal Entities of Mexico. It is divided in 20 municipalities and its ...

: Except for the Bahía de Banderas municipality, which uses the Central Time Zone. :*

– no

, always on MST. :* Sinaloa :* Revillagigedo Islands ( Colima): three of the four islands have the same time as Mountain Time Zone, Isla Socorro,

San Benedicto Island San Benedicto, formerly Isla de los Innocentes, is an uninhabited island, and third largest island of the Revillagigedo Islands, located in the Pacific Ocean. It is 4.8 km by 2.4 km in size, with an area 10 km². It is of volcanic ...

and Roca Partida.

United States

Six states are fully contained in the Mountain Time Zone: *

Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...

Montana Montana () is a U.S. state, state in the Mountain states, Mountain West List of regions of the United States#Census Bureau-designated regions and divisions, division of the Western United States. It is bordered by Idaho to the west, North ...

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...

Wyoming Wyoming () is a state in the Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to the sou ...

(does not use daylight saving time except for Navajo Nation) Three states are split between the Mountain Time Zone and the Pacific Time Zone. The following locations observe Mountain Time: *

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and W ...

: Southern Idaho *

Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idah ...

: the majority of Malheur County *

Nevada Nevada ( ; ) is a state in the Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the 7th-most extensive, ...

West Wendover West Wendover is a small city in Elko County, Nevada, United States. The population was 4,410 at the 2010 census. It is part of the Elko micropolitan area. West Wendover is located on the eastern border of Nevada and the western edge of the Gr ...

Five states are split between the Mountain Time Zone and the

. The following locations observe Mountain Time: *

Kansas Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to ...

: Sherman, Wallace, Greeley and Hamilton counties *

Nebraska Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the so ...

: western third *

North Dakota North Dakota () is a U.S. state in the Upper Midwest, named after the indigenous Dakota Sioux. North Dakota is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minnesota to the east, S ...

: the SW corner counties (

Adams Adams may refer to: * For persons, see Adams (surname) Places United States *Adams, California *Adams, California, former name of Corte Madera, California *Adams, Decatur County, Indiana *Adams, Kentucky *Adams, Massachusetts, a New England town ...

, Billings, Bowman, Golden Valley, Grant, Hettinger,

Slope In mathematics, the slope or gradient of a line is a number that describes both the ''direction'' and the ''steepness'' of the line. Slope is often denoted by the letter ''m''; there is no clear answer to the question why the letter ''m'' is used ...

, Stark) observe MST. The counties of McKenzie, Dunn, and Sioux are split. *

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota people, Lakota and Dakota peo ...

: western half *

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

: El Paso, Hudspeth, and northwestern Culberson counties

Major metropolitan areas

The following is a list of major cities located within the Mountain Time Zone, ordered alphabetically. * Albuquerque, New Mexico * Arvada, Colorado * Aurora, Colorado * Boise, Idaho * Boulder, Colorado *

Billings, Montana Billings is the largest city in the U.S. state of Montana, with a population of 117,116 as of the 2020 census. Located in the south-central portion of the state, it is the seat of Yellowstone County and the principal city of the Billings Metr ...

Calgary Calgary ( ) is the largest city in the western Canadian province of Alberta and the largest metro area of the three Prairie Provinces. As of 2021, the city proper had a population of 1,306,784 and a metropolitan population of 1,481,806, maki ...

* Centennial, Colorado * Chandler, Arizona * Chihuahua, Chihuahua * Ciudad Juárez,

Chihuahua Chihuahua may refer to: Places *Chihuahua (state), a Mexican state **Chihuahua (dog), a breed of dog named after the state **Chihuahua cheese, a type of cheese originating in the state **Chihuahua City, the capital city of the state **Chihuahua Mun ...

* Ciudad Obregón,

* Colorado Springs, Colorado * Culiacán, Sinaloa *

Denver Denver () is a consolidated city and county, the capital, and most populous city of the U.S. state of Colorado. Its population was 715,522 at the 2020 census, a 19.22% increase since 2010. It is the 19th-most populous city in the United ...

Edmonton Edmonton ( ) is the capital city of the Canadian province of Alberta. Edmonton is situated on the North Saskatchewan River and is the centre of the Edmonton Metropolitan Region, which is surrounded by Alberta's central region. The city anc ...

El Paso, Texas El Paso (; "the pass") is a city in and the seat of El Paso County in the western corner of the U.S. state of Texas. The 2020 population of the city from the U.S. Census Bureau was 678,815, making it the 23rd-largest city in the U.S., the ...

Flagstaff, Arizona Flagstaff ( ) is a city in, and the county seat of, Coconino County in northern Arizona, in the southwestern United States. In 2019, the city's estimated population was 75,038. Flagstaff's combined metropolitan area has an estimated population ...

* Fort Collins, Colorado * Gilbert, Arizona * Glendale, Arizona *

Greeley, Colorado Greeley is the home rule municipality city that is the county seat and the most populous municipality of Weld County, Colorado, United States. The city population was 108,795 at the 2020 United States Census, an increase of 17.12% since the ...

* Hermosillo,

* La Paz, Baja California Sur * Lake Havasu City, Arizona * Lakewood, Colorado * Lethbridge,

* Los Mochis, Sinaloa *

Mazatlán Mazatlán () is a city in the Mexican state of Sinaloa. The city serves as the municipal seat for the surrounding '' municipio'', known as the Mazatlán Municipality. It is located at on the Pacific coast, across from the southernmost tip ...

, Sinaloa * Mesa, Arizona *

Missoula, Montana Missoula ( ; fla, label= Séliš, Nłʔay, lit=Place of the Small Bull Trout, script=Latn; kut, Tuhuⱡnana, script=Latn) is a city in the U.S. state of Montana; it is the county seat of Missoula County. It is located along the Clark Fork Ri ...

* Nogales, Sonora * Peoria, Arizona *

* Provo, Utah *

Pueblo, Colorado Pueblo () is a home rule municipality that is the county seat and the most populous municipality of Pueblo County, Colorado, United States. The city population was 111,876 at the 2020 United States Census, making Pueblo the ninth most popu ...

* Rapid City, South Dakota * Red Deer, Alberta *

Salt Lake City Salt Lake City (often shortened to Salt Lake and abbreviated as SLC) is the capital and most populous city of Utah, United States. It is the seat of Salt Lake County, the most populous county in Utah. With a population of 200,133 in 2020, th ...

* San Luis Río Colorado,

* Scottsdale, Arizona * Surprise, Arizona * Tempe, Arizona * Tepic,

* Thornton, Colorado *

Tucson, Arizona , "(at the) base of the black ill , nicknames = "The Old Pueblo", "Optics Valley", "America's biggest small town" , image_map = , mapsize = 260px , map_caption = Interactive ...

* West Jordan, Utah * West Valley City, Utah * Westminster, Colorado *

Yuma, Arizona Yuma ( coc, Yuum) is a city in and the county seat of Yuma County, Arizona, United States. The city's population was 93,064 at the 2010 census, up from the 2000 census population of 77,515. Yuma is the principal city of the Yuma, Arizona, M ...

Notes

References

External links

World time zone map

History of U.S. time zones and UTC conversion

Official times across Canada

Official times across Mexico

U.S. time map
{{North American time zones Time zones Time in Canada Time in Mexico Time zones in the United States