Mountain Time Zone

{{Infobox time zone |title = Mountain Time Zone |image = North American Time Zones 2026.png |caption = {{legend|#8ac56d|Mountain Time Zone}} Shown offsets are Standard |offset = −07:00 |dst offset = −06:00 |initials = MST |dst initials = MDT |dst use = some |format = }}

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).

In Canada, Mexico, and the United States, 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.

Most of Mexico, and most of Arizona in the United States, do not observe daylight saving time (DST), and during the spring, summer, and autumn months they are on the same time as Pacific Daylight Time.<ref>{{cite news |last=Robbins |first=Ted |date=March 11, 2007 |title=Arizona Says No to Daylight-Saving Time |url=https://www.npr.org/templates/story/story.php?storyId=7829863 |work=Weekend Edition Sunday |publisher=National Public Radio |access-date=June 18, 2012 |archive-date=January 20, 2022 |archive-url=https://web.archive.org/web/20220120112155/https://www.npr.org/templates/story/story.php?storyId=7829863 |url-status=live }}</ref> The Canadian province of British Columbia observes permanent daylight saving time in the Pacific Time Zone, which is equivalent to year-round Mountain Standard Time.

The largest city in the Mountain Time Zone is Phoenix, Arizona; the Phoenix metropolitan area is the largest metropolitan area in the zone. The largest city that observes daylight saving time is Juárez, Chihuahua, Mexico.

The clock time in this zone is based on the mean solar time at the 105th meridian west of the Greenwich Observatory. In the United States, the exact specification for the location of time zones and the dividing lines between zones is set forth in the Code of Federal Regulations at 49 CFR 71.{{#tag:ref|The specification for the Mountain Time Zone in the United States is set forth at 49 CFR 71.8.<ref>{{Cite web |url=http://edocket.access.gpo.gov/cfr_2008/octqtr/49cfr71.8.htm |title=49 CFR 71.8 Mountain zone |work=Code of Federal Regulations |access-date=October 7, 2011 |archive-date=January 13, 2012 |archive-url=https://web.archive.org/web/20120113014917/http://edocket.access.gpo.gov/cfr_2008/octqtr/49cfr71.8.htm |url-status=live }}</ref> The boundary between Central and Mountain time zones is set forth at 49 CFR 71.7,<ref>{{Cite web |url=http://edocket.access.gpo.gov/cfr_2008/octqtr/49cfr71.7.htm |title= 49 CFR 71.7 Boundary line between central and mountain zones |work= Code of Federal Regulations |access-date= October 7, 2011}}</ref> and the boundary between Mountain and Pacific time zones is set forth at 49 CFR 71.9.<ref>{{Cite web |url= http://edocket.access.gpo.gov/cfr_2008/octqtr/49cfr71.9.htm |title= 49 CFR 71.9 Boundary line between mountain and Pacific zones |work= Code of Federal Regulations |access-date= October 7, 2011 |archive-date= January 14, 2012 |archive-url= https://web.archive.org/web/20120114104752/http://edocket.access.gpo.gov/cfr_2008/octqtr/49cfr71.9.htm |url-status= live }}</ref>|name=name|group=lower-alpha}}

==Canada== {{main|Time in Canada}}

Two provinces and two territories are fully contained in the Mountain Time Zone: *Alberta *British Columbia (no DST in most of province) *Northwest Territories *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.<ref>{{Cite web |title=HOME - Yukon Legislation |url=https://laws.yukon.ca/cms/ |access-date=February 16, 2022 |website=Yukon Legislation}}</ref>

On March 8, 2026, most of British Columbia in the Pacific Time Zone adopted UTC−7 year-round but continue to call their time zone "Pacific Time". Southeastern parts of the province (near the Alberta border) continue to observe daylight saving time: UTC−6 in the summer and UTC−7 in the winter.<ref name="BC permanent DST">{{cite web|url=https://news.gov.bc.ca/releases/2026AG0013-000209|title=Adopting permanent daylight saving time|date=March 2, 2026|accessdate=March 2, 2026|work=BC Gov News|publisher=Government of British Columbia|quote=At that point, the transition to Pacific time, the name of B.C.’s new time zone, will be complete. Pacific time will be set seven hours behind co-ordinated universal time (UTC−7), matching the current offset used during daylight saving time.}}</ref>

One territory and one province are split between the Mountain Time Zone and the Central Time Zone: *Nunavut – Kitikmeot Region *Saskatchewan – Lloydminster and vicinity

==Mexico== {{main|Time in Mexico}}

As of October 30, 2022, Mexico abandoned daylight saving time, with certain exceptions. The following states have an offset equal to Mountain Standard Time, there called the {{lang |es |Zona Pacifico}} (Pacific Zone):

*Baja California Sur *Nayarit: except for the Bahía de Banderas municipality, which uses the Central Time Zone. *Sonora *Sinaloa *Chihuahua: Observes Daylight Savings Time, only in northwestern border municipalities (Janos, Ascensión, Juárez, Guadalupe, and Práxedis Gilberto Guerrero) *Revillagigedo Islands (Colima): three of the four islands have the same time as Mountain Time Zone: Socorro Island, San Benedicto Island and Roca Partida.

The following states have an offset equal to Mountain Daylight Time or Central Standard Time, there called the {{lang |es |Zona Centro}} (Central Zone):

{{div col|colwidth=20em}} *Aguascalientes *Campeche *Chihuahua, except for the northwestern border area (which follows MST/MDT) and northeastern border area (follows CST/CDT) *Ciudad de México *Coahuila, except for northern border areas (CST/CDT) *Colima, except all of the Revillagigedo Islands. *Chiapas *Durango *Guanajuato *Guerrero *Hidalgo *Jalisco *México *Michoacán *Morelos *Nuevo León, except for northern border areas (CST/CDT) *Oaxaca *Puebla *Querétaro *San Luis Potosí *Tabasco *Tamaulipas, except for northern border areas (CST/CDT) *Tlaxcala *Veracruz *Yucatán *Zacatecas *Municipality of Bahía de Banderas in Nayarit {{div col end}}

==United States== {{main|Time in the United States}}

Six states are fully contained in the Mountain Time Zone: *Colorado *Montana *New Mexico *Utah *Wyoming *Arizona (does not observe 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 and the portion of Idaho County south of the Salmon River *Oregon: the majority of Malheur County *Nevada: West Wendover **The communities of Jackpot, Jarbidge, Mountain City, and Owyhee unofficially observe Mountain Time, although they are officially within the Pacific Time Zone.<ref>{{Cite web |title=OnTimeZone.com Exceptions, Oddities and Notes |url=http://ontimezone.com/exceptions.php |archive-url=https://web.archive.org/web/20140318195224/http://ontimezone.com/exceptions.php |archive-date=2014-03-18 |access-date=2025-08-09 |website=ontimezone.com}}</ref> Five states are split between the Mountain Time Zone and the Central Time Zone. The following locations observe Mountain Time: *Kansas: Sherman, Wallace, Greeley and Hamilton counties *Nebraska: western one third *North Dakota: the southwest corner counties (Adams, Billings, Bowman, Golden Valley, Grant, Hettinger, Slope, Stark) observe MST. The counties of McKenzie, Dunn, and Sioux are split. *South Dakota: western half *Texas: El Paso, Hudspeth, and northwestern Culberson counties

== Major metropolitan areas == Alphabetical list of major cities located within the Mountain Time Zone. Cities in '''bold''' do not observe daylight saving time: {{div col|colwidth=20em}} * Albuquerque, New Mexico * Billings, Montana * Boise, Idaho * Boulder, Colorado * Calgary, Alberta * Cheyenne, Wyoming * Ciudad Juárez, Chihuahua * '''Ciudad Obregón, Sonora''' * Colorado Springs, Colorado * '''Culiacán, Sinaloa''' *Metropolitan Denver **Arvada, Colorado ** Aurora, Colorado ** Centennial, Colorado ** Denver, Colorado ** Lakewood, Colorado ** Westminster, Colorado * Edmonton, Alberta * El Paso, Texas * '''Flagstaff, Arizona''' * Fort Collins, Colorado * Greeley, Colorado * '''Hermosillo, Sonora''' * '''La Paz, Baja California Sur''' * Lake Havasu City, Arizona * Las Cruces, New Mexico * Lethbridge, Alberta * '''Los Mochis, Sinaloa''' * '''Mazatlán, Sinaloa''' * Missoula, Montana * '''Nogales, Sonora''' * '''Metropolitan Phoenix''' ** '''Chandler, Arizona''' ** '''Gilbert, Arizona''' ** '''Glendale, Arizona''' ** '''Mesa, Arizona''' ** '''Peoria, Arizona''' ** '''Phoenix, Arizona''' ** '''Surprise, Arizona''' ** '''Tempe, Arizona''' * Pueblo, Colorado * Rapid City, South Dakota * Red Deer, Alberta * '''San Luis Río Colorado, Sonora''' * '''Tepic, Nayarit''' * '''Tucson, Arizona''' * Wasatch Front ** Orem, Utah ** Provo, Utah ** Salt Lake City, Utah ** West Jordan, Utah ** West Valley City, Utah * '''Vancouver, British Columbia''' * '''Yuma, Arizona''' {{div col end}}

==Notes== {{reflist|group=lower-alpha}}

==References== {{reflist}}

==External links== * [http://www.travel.com.hk/region/timezone.htm World time zone map] {{Webarchive|url=https://web.archive.org/web/20151224150321/http://www.travel.com.hk/region/timezone.htm |date=December 24, 2015 }} * [http://geography.about.com/library/misc/ntimezones.htm U.S. time zone map] {{Webarchive|url=https://web.archive.org/web/20090215175709/http://geography.about.com/library/misc/ntimezones.htm |date=February 15, 2009 }} * [http://aa.usno.navy.mil/faq/docs/us_tzones.php History of U.S. time zones and UTC conversion] {{Webarchive|url=https://web.archive.org/web/20110808232828/http://aa.usno.navy.mil/faq/docs/us_tzones.php |date=August 8, 2011 }} * [http://www.worldtimezone.com/time-canada12.html Canada time zone map] * [http://www.cenam.mx/hora_oficial/ Official times across Mexico] * [http://24timezones.com/ca_map/canada_time.htm Canada time map] * [http://24timezones.com/us_clock/usa_time.php U.S. time map]

Category:Time in Canada Category:Time in Mexico Category:Time zones in the United States Category:Time zones