Mountain Time Zone

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Mountain Time Zone
Time zone
Timezoneswest.PNG
  Mountain Time Zone
UTC offset
MST UTC−07:00
MDT UTC−06:00
Current time
11:05, January 31, 2024 MST [refresh]
Observance of DST
DST is observed in some of this time zone.

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 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. [lower-alpha 1]

Contents

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 to New Mexico. In Mexico, this time zone is known as the tiempo de la montaña or zona Pacífico ("Pacific Zone"). In the United States and Canada, the Mountain Time Zone is to the east of the Pacific Time Zone and to the west of the Central Time Zone.

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

Sonora in 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. [4] 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; the Phoenix metropolitan area is the largest metropolitan area in the zone.

Canada

One province and two territories are fully contained in the Mountain Time Zone:

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. [5]

One province and one territory are split between the Mountain Time Zone and the Pacific Time Zone:

One territory and one province are split between the Mountain Time Zone and the Central Time Zone:

Mexico

The following states have the same time as Mountain Time Zone:

United States

Six states are fully contained in the Mountain Time Zone:

Three states are split between the Mountain Time Zone and the Pacific Time Zone. The following locations observe Mountain Time:

Five states are split between the Mountain Time Zone and the Central Time Zone. The following locations observe Mountain Time:

Major metropolitan areas

Alphabetical list of major cities located within the Mountain Time Zone:

See also

Notes

  1. The specification for the Mountain Time Zone in the United States is set forth at 49 CFR 71.8. [1] The boundary between Central and Mountain time zones is set forth at 49 CFR 71.7, [2] and the boundary between Mountain and Pacific time zones is set forth at 49 CFR 71.9. [3]

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The Eastern Time Zone (ET) is a time zone encompassing part or all of 23 states in the eastern part of the United States, parts of eastern Canada, and the state of Quintana Roo in Mexico.

<span class="mw-page-title-main">Pacific Time Zone</span> North American time zone

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). During daylight saving time, a time offset of UTC−07:00 is used.

<span class="mw-page-title-main">Time in the United States</span> U.S. time zones

In the United States, time is divided into nine standard time zones covering the states, territories and other US possessions, with most of the country observing daylight saving time (DST) for approximately the spring, summer, and fall months. The time zone boundaries and DST observance are regulated by the Department of Transportation, but no single map of those existed until the agency announced intentions to make one in September 2022. Official and highly precise timekeeping services (clocks) are provided by two federal agencies: the National Institute of Standards and Technology (NIST) ; and the United States Naval Observatory (USNO). The clocks run by these services are kept synchronized with each other as well as with those of other international timekeeping organizations.

<span class="mw-page-title-main">Uniform Time Act</span> United States timekeeping and daylight saving time law

The Uniform Time Act of 1966, Pub. L.Tooltip Public Law  89–387, 80 Stat. 107, enacted April 13, 1966, was a Law of the United States to "promote the adoption and observance of uniform time within the standard time zones" prescribed by the Standard Time Act of 1918. Its intended effect was to simplify the official pattern of where and when daylight saving time (DST) is applied within the U.S. Prior to this law, each state had its own scheme for when DST would begin and end, and in some cases, which parts of the state should use it.

Yukon Standard Time The Yukon is permanently 7 hours behind Coordinated Universal Time. In the Yukon, no "spring forward" or "fall back".

<span class="mw-page-title-main">UTC−07:00</span> Identifier for a time offset from UTC of −7

UTC−07:00 is an identifier for a time offset from UTC of −07:00. In North America, it is observed in the Mountain Time Zone during standard time, and in the Pacific Time Zone during the other eight months. Some locations use it year-round.

<span class="mw-page-title-main">UTC−06:00</span> Identifier for a time offset from UTC of −6

UTC−06:00 is an identifier for a time offset from UTC of −06:00. In North America, it is observed in the Central Time Zone during standard time, and in the Mountain Time Zone during the other eight months. Several Latin American countries and a few other places use it year-round.

<span class="mw-page-title-main">Time in Australia</span> Time zones in Australia

Australia uses three main time zones: Australian Eastern Standard Time, Australian Central Standard Time and Australian Western Standard Time.

<span class="mw-page-title-main">Time in Canada</span> Time zones of Canada

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<span class="mw-page-title-main">Chamorro Time Zone</span> Time zone for Guam and Northern Mariana Islands

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<span class="mw-page-title-main">Time in Mexico</span> Time zones used in Mexico

Mexico uses four time zones:

<span class="mw-page-title-main">Mountain states</span> Region of the United States

The Mountain states form one of the nine geographic divisions of the United States that are officially recognized by the United States Census Bureau. It is a subregion of the Western United States.

In Canada, daylight saving time (DST) is observed in nine of the country's ten provinces and two of its three territories—though with exceptions in parts of several provinces and Nunavut.

Most of Mexico no longer observes daylight saving time as it was abolished on Sunday, 30 October 2022. The exceptions are the entire state of Baja California, as well as the border municipalities in Chihuahua, Coahuila, Nuevo León, and Tamaulipas which still observe daylight savings time matching the schedule of the United States beginning on the second Sunday of March and ending on the first Sunday of November.

Daylight saving time in the Americas is the arrangement in the Americas by which clocks are advanced by one hour in spring and moved back in autumn, to make the most of seasonal daylight. The practice is widespread in North America, with most of Canada and the United States participating, but much less so in Central and South America.

Alaska is officially covered by two time zones - the Alaska Time Zone and the Hawaii-Aleutian Time Zone. The Hawaii-Aleutian Time Zone is used for the Aleutian Islands west of 169°30′W, and the rest of the state uses the Alaska Time Zone. The entirety of Alaska observes daylight saving time.

<span class="mw-page-title-main">Time in Arizona</span> Time Standard in the state of Arizona.

Time in Arizona, as in all U.S. states, is regulated by the United States Department of Transportation as well as by state and tribal law.

<span class="mw-page-title-main">Time in Idaho</span>

The U.S. state of Idaho is covered by two time zones, as described below. All locations observe daylight saving time.

References

  1. "49 CFR 71.8 Mountain zone". Code of Federal Regulations . Retrieved October 7, 2011.
  2. "49 CFR 71.7 Boundary line between central and mountain zones". Code of Federal Regulations. Retrieved October 7, 2011.
  3. "49 CFR 71.9 Boundary line between mountain and Pacific zones". Code of Federal Regulations. Retrieved October 7, 2011.
  4. Robbins, Ted (March 11, 2007). "Arizona Says No to Daylight-Saving Time". Weekend Edition Sunday . National Public Radio . Retrieved June 18, 2012.
  5. "HOME - Yukon Legislation". Yukon Legislation. Retrieved February 16, 2022.