Mountain Time Zone Map

Offset and daylight saving

Mountain Standard Time (MST) is UTC−7. Mountain Daylight Time (MDT), UTC−6, runs from the second Sunday in March to the first Sunday in November everywhere in the zone except Arizona. Arizona has not observed daylight time since 1968, so in summer Phoenix matches Los Angeles (Pacific Daylight Time is also UTC−7) and in winter it matches Denver. The exception inside the exception is the Navajo Nation, which covers the north-east corner of Arizona and does observe daylight time, while the Hopi Reservation inside the Navajo Nation does not.

States fully in the Mountain zone

Six states lie entirely in the zone, with a combined 2020 population of 19,975,430. Arizona alone accounts for 7,151,502 of that; Wyoming, with 576,851, is the least populous state in the country.

State	Code	Capital	Population (2020)
Arizona	AZ	Phoenix	7,151,502
Colorado	CO	Denver	5,773,714
Montana	MT	Helena	1,084,225
New Mexico	NM	Santa Fe	2,117,522
Utah	UT	Salt Lake City	3,271,616
Wyoming	WY	Cheyenne	576,851

States partly in the Mountain zone

Eight states are split. Idaho is the largest case: the zone boundary follows the Salmon River, so the panhandle north of it keeps Pacific time with Spokane, Washington, while Boise and the Snake River plain are Mountain. On the east side, the boundary with Central cuts through the Dakotas, Nebraska, Kansas and Texas, generally leaving the sparsely populated western fringe of each on Mountain time.

State	Part in this zone	Rest of the state
Idaho	Southern Idaho, including Boise, Idaho Falls and Pocatello	Northern panhandle north of the Salmon River (Coeur d'Alene, Moscow, Lewiston) is Pacific
Kansas	Four western counties: Sherman, Wallace, Greeley, Hamilton	Rest of the state is Central
Nebraska	Western Panhandle (Scottsbluff, Alliance) and several central counties	Eastern two-thirds, including Omaha and Lincoln, is Central
Nevada	West Wendover only	Rest of the state is Pacific
North Dakota	South-west corner: Dickinson, Bowman, Hettinger	Rest of the state, including Bismarck and Fargo, is Central
Oregon	Most of Malheur County (Ontario)	Rest of the state is Pacific
South Dakota	Western half: Rapid City, the Black Hills	Eastern half, including Sioux Falls and Pierre, is Central
Texas	El Paso and Hudspeth counties	Rest of the state is Central

Major cities on Mountain time

City	Population (2020)
Phoenix, AZ	1,608,139
Denver, CO	715,522
El Paso, TX	678,815
Albuquerque, NM	564,559
Tucson, AZ	542,629
Mesa, AZ	504,258
Colorado Springs, CO	478,961
Salt Lake City, UT	199,723
Boise, ID	235,684

Cheyenne, Billings, Santa Fe, Helena and Rapid City are also on Mountain time. Phoenix is the fifth-largest US city and the largest that does not change its clocks.

Where the boundaries run

With Central (east): from the Canadian border the line runs south through western North Dakota, along the Missouri River through South Dakota, across the Nebraska Sandhills, around the four western counties of Kansas, then along the Colorado and New Mexico state lines to the Rio Grande at El Paso. With Pacific (west): the Montana–Idaho state line down the Continental Divide as far as the Salmon River, the Salmon River across Idaho, the Idaho–Oregon and Idaho–Nevada state lines (with the Ontario, Oregon and West Wendover, Nevada exceptions), and the Nevada–Arizona line along the Colorado River.

Converting from Mountain

Noon Mountain is 2 pm Eastern, 1 pm Central, 11 am Pacific, 10 am Alaska, 9 am Hawaii (8 am during daylight time).
Noon MST is 19:00 UTC; noon MDT is 18:00 UTC. Arizona is 19:00 UTC all year.
Between March and November Phoenix and Los Angeles show the same time; between November and March Phoenix and Denver do.

Other zones

Eastern · Central · Pacific · Alaska · Hawaii-Aleutian · all zones

Region maps for the same area: Mountain division, Rocky Mountain states, Southwest. See also the Continental Divide, which the zone's western boundary follows through Montana.