The Mountain Time Zone of North America keeps time by subtracting seven hours from Coordinated Universal Time (UTC) when standard time ( UTC−07:00) is in effect, and by subtracting six hours during daylight saving time ( 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 ...

of the

Greenwich Observatory The Royal Observatory, Greenwich (ROG; known as the Old Royal Observatory from 1957 to 1998, when the working Royal Greenwich Observatory, RGO, temporarily moved south from Greenwich to Herstmonceux) is an observatory situated on a hill in G ...

. 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 it ...

s and the dividing lines between zones is set forth in the Code of Federal Regulations 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 The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico ...

, which range from

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

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ke ...

. 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 in Mexico and most of

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

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 Pacific Time Zone (PT) is a time zone encompassing parts of western Canada, the western United States, and western Mexico. Places in this zone observe standard time by subtracting eight hours from Coordinated Universal Time ( UTC−08:00 ...

. 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 on ...

; 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 Yukon (; ; formerly called Yukon Territory and also referred to as the Yukon) is the smallest and westernmost of Canada's three territories. It also is the second-least populated province or territory in Canada, with a population of 43,964 as ...

(no DST) On September 24, 2020,

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

* Nunavut: Kitikmeot Region * Saskatchewan:

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 administrati ...

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. :* Sonora – no daylight saving time, always on MST. :* Sinaloa :*

Revillagigedo Islands The Revillagigedo Islands ( es, Islas Revillagigedo, ) or Revillagigedo Archipelago are a group of four volcanic islands in the Pacific Ocean, known for their unique ecosystem. They lie approximately from Socorro Island south and southwest of C ...

(

Colima Colima (), officially the Free and Sovereign State of Colima ( es, Estado Libre y Soberano de Colima), is one of the 31 states that make up the 32 Federal Entities of Mexico. It shares its name with its capital and main city, Colima. Colima i ...

): three of the four islands have the same time as Mountain Time Zone,

Isla Socorro Socorro Island ( es, Isla Socorro) is a small volcanic island in the Revillagigedo Islands, a Mexican possession lying off the country's western coast. The size is 16.5 by 11.5 km (10.25 by 7.15 miles), with an area of . It is the largest ...

, San Benedicto Island and

Roca Partida Roca Partida ( en, Split Rock) ranks as the smallest of the four Revillagigedo Islands, part of the Free and Sovereign State of Colima in Mexico. The uninhabited island (Latitude 19° 0'2.53"N, Longitude 112° 4'5.35"W) encompasses an extremely sm ...

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 state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...

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 it ...

* Wyoming *

(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: 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 Idaho. T ...

: 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 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 th ...

: 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 sout ...

: western third * North Dakota: the SW corner counties ( Adams, Billings, Bowman, Golden Valley,

Grant Grant or Grants may refer to: Places *Grant County (disambiguation) Australia * Grant, Queensland, a locality in the Barcaldine Region, Queensland, Australia United Kingdom * Castle Grant United States * Grant, Alabama * Grant, Inyo County, ...

, 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 use ...

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

South Dakota South Dakota (; Sioux: , ) is a U.S. state in the North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota and Dakota Sioux Native American tribes, who comprise a large porti ...

: western half *

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

: 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 Aurora (, ) is a home rule municipality located in Arapahoe, Adams, and Douglas counties, Colorado, United States. The city's population was 386,261 at the 2020 United States Census with 336,035 residing in Arapahoe County, 47,720 residing in ...

Boise, Idaho Boise (, , ) is the capital and most populous city of the U.S. state of Idaho and is the county seat of Ada County. On the Boise River in southwestern Idaho, it is east of the Oregon border and north of the Nevada border. The downtown ar ...

* Boulder, Colorado * Billings, Montana * Calgary,

Centennial, Colorado Centennial is a home rule municipality located in Arapahoe County, Colorado, United States. The city population was 108,418 at the 2020 United States Census, making Centennial the 11th most populous municipality in Colorado. Centennial is a part ...

* Chandler, Arizona * Chihuahua, Chihuahua * Ciudad Juárez, Chihuahua * Ciudad Obregón, Sonora * Colorado Springs, Colorado *

Culiacán Culiacán, officially Culiacán Rosales, is a city in northwestern Mexico, the capital and largest city of both the Culiacán Municipality and the state of Sinaloa. The city was founded on 29 September 1531, by the Spanish conquerors Lázar ...

, Sinaloa * Denver,

* Edmonton,

El Paso, Texas El Paso (; "the pass") is a city in and the county seat, seat of El Paso County, Texas, El Paso County in the western corner of the U.S. state of Texas. The 2020 population of the city from the United States Census Bureau, U.S. Census Bureau w ...

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

Greeley, Colorado Greeley is the List of municipalities in Colorado#Home rule municipality, home rule municipality city that is the county seat and the List of municipalities in Colorado, most populous municipality of Weld County, Colorado, Weld County, Colorado, ...

Hermosillo Hermosillo (), formerly called Pitic (as in ''Santísima Trinidad del Pitic'' and ''Presidio del Pitic''), is a city located in the center of the northwestern Mexican state of Sonora. It is the municipal seat of the Hermosillo municipality, the ...

, Sonora *

La Paz, Baja California Sur La Paz (, en, Peace) is the capital city of the Mexican state of Baja California Sur and an important regional commercial center. The city had a 2020 census population of 250,141 inhabitants, making it the most populous city in the state. Its ...

Lake Havasu City, Arizona Lake Havasu City (, ) is a city in Mohave County, Arizona, United States. As of the 2020 census, the population of the city was 57,144, up from 52,527 in 2010. It is served by Lake Havasu City Airport. History The community first started as a ...

* Lakewood, Colorado * Lethbridge,

Los Mochis Los Mochis () is a coastal city in northern Sinaloa, Mexico. It serves as the municipal seat of the municipality of Ahome. As of the 2010 census, the population was 362,613, which was 61 percent of the municipality's population. Los Mochis is th ...

, 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 ...

Nogales, Sonora Heroica Nogales (), more commonly known as Nogales, is a city and the county seat of the Municipality of Nogales. It is located on the northern border of the Mexican state of Sonora. The city is abutted on its north by the city of Nogales, Arizo ...

Peoria, Arizona Peoria is a city in Maricopa and Yavapai counties in the state of Arizona. Most of the city is located in Maricopa County, while a portion in the north is in Yavapai County. It is a major suburb of Phoenix. As of the 2020 census, the popul ...

* Provo, Utah * Pueblo, Colorado * 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, Sonora * Scottsdale, Arizona * Surprise, Arizona * Tempe, Arizona * Tepic,

Thornton, Colorado The City of Thornton is a home rule municipality located in Adams and Weld counties, Colorado, United States. The city population was 141,867, all in Adams County, at the 2020 United States Census, an increase of +19.44% since the 2010 United ...

* Tucson, Arizona *

West Jordan, Utah West Jordan is a city in Salt Lake County, Utah, United States. It is a suburb of Salt Lake City and has a mixed economy. According to the 2020 Census, the city had a population of 116,961, placing it as the third most populous in the state. T ...

* West Valley City, Utah *

Westminster, Colorado The City of Westminster is a home rule municipality located in Adams and Jefferson counties, Colorado, United States. The city population was 116,317 at the 2020 United States Census with 71,240 residing in Adams County and 45,077 residing in ...

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