|Mountain Time Zone|
MST or UTC−07:00
|00:07, April 21, 2019 MDT|
|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 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.
North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere; it is also considered by some to be a northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea.
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is within about 1 second of mean solar time at 0° longitude, and is not adjusted for daylight saving time. In some countries where English is spoken, the term Greenwich Mean Time (GMT) is often used as a synonym for UTC and predates UTC by nearly 300 years.
Standard time is the synchronization of clocks within a geographical area or region to a single time standard, rather than using solar time or a locally chosen meridian (longitude) to establish a local mean time standard. Historically, the concept was established during the 19th century to aid weather forecasting and train travel. Applied globally in the 20th century, the geographical areas became extended around evenly spaced meridians into time zones which (usually) centered on them. The standard time set in each time zone has come to be defined in terms of offsets from Universal Time. In regions where daylight saving time is used, that time is defined by another offset, from the standard time in its applicable time zones.
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 how the Rocky Mountains, which range from northwestern Canada to the US state of New Mexico, are located almost entirely in the time zone. In Mexico, this time zone is known as the Zona Pacífico (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 United States of America (USA), commonly known as the United States or America, is a country comprising 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is slightly smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U.S. is the third most populous country. The capital is Washington, D.C., and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico. The State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean. The U.S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The extremely diverse geography, climate, and wildlife of the United States make it one of the world's 17 megadiverse countries.
Canada is a country in the northern part of North America. Its ten provinces and three territories extend from the Atlantic to the Pacific and northward into the Arctic Ocean, covering 9.98 million square kilometres, making it the world's second-largest country by total area. Canada's southern border with the United States, stretching some 8,891 kilometres (5,525 mi), is the world's longest bi-national land border. Its capital is Ottawa, and its three largest metropolitan areas are Toronto, Montreal, and Vancouver. As a whole, Canada is sparsely populated, the majority of its land area being dominated by forest and tundra. Consequently, its population is highly urbanized, with over 80 percent of its inhabitants concentrated in large and medium-sized cities, with 70% of citizens residing within 100 kilometres (62 mi) of the southern border. Canada's climate varies widely across its vast area, ranging from arctic weather in the north, to hot summers in the southern regions, with four distinct seasons.
The Rocky Mountains, also known as the Rockies, are a major mountain range in western North America. The Rocky Mountains stretch more than 4,800 kilometers (3,000 mi) from the northernmost part of British Columbia, in western Canada, to New Mexico in the Southwestern United States. Located within the North American Cordillera, the Rockies are somewhat distinct from the Pacific Coast Ranges, Cascade Range, and the Sierra Nevada, which all lie farther to the west.
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, 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 Nation, as well as some Arizona state offices lying within the Navajo Nation, do not.
Sonora, officially Estado Libre y Soberano de Sonora, is one of 31 states that, with Mexico City, comprise the 32 federal entities of United Mexican States. It is divided into 72 municipalities; the capital city is Hermosillo. Sonora is bordered by the states of Chihuahua to the east, Baja California to the northwest and Sinaloa to the south. To the north, it shares the U.S.–Mexico border with the states of Arizona and New Mexico, and on the west has a significant share of the coastline of the Gulf of California.
Arizona is a state in the southwestern region of the United States. It is also part of the Western and the Mountain states. It is the sixth largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona shares the Four Corners region with Utah, Colorado, and New Mexico; its other neighboring states are Nevada and California to the west and the Mexican states of Sonora and Baja California to the south and southwest.
The Navajo Nation is a Native American territory covering about 17,544,500 acres, occupying portions of northeastern Arizona, southeastern Utah, and northwestern New Mexico in the United States. This is the largest land area retained by a Native American tribe, with a population of roughly 350,000 as of 2016.
The largest city in the Mountain Time Zone is Phoenix, Arizona. The Phoenix metropolitan area is the largest metropolitan area in the zone; the next largest metropolitan area that observes Mountain Time is Denver, closely followed by the El Paso–Juárez area. TV broadcasting in the Mountain Time Zone is typically tape-delayed one hour, so that shows match the broadcast times of the Central Time Zone (i.e. prime time begins at 7 pm MT following the same order of programming as the Central Time Zone).[ citation needed ]
Phoenix is the capital and most populous city of Arizona, with 1,626,000 people. It is also the fifth most populous city in the United States, and the most populous American state capital, and the only state capital with a population of more than one million residents.
The Phoenix Metropolitan Area – often referred to as the Valley of the Sun, the Salt River Valley, or Metro Phoenix – is a metropolitan area, centered on the city of Phoenix, that includes much of the central part of the U.S. State of Arizona. The United States Office of Management and Budget designates the area as the Phoenix-Mesa-Scottsdale Metropolitan Statistical Area (MSA), defining it as Maricopa and Pinal counties. As of the Census Bureau's 2017 population estimates, Metro Phoenix had 4,737,270 residents, making it the 11th largest Metropolitan Area in the nation by population. The gross domestic product of the Phoenix Metropolitan Area was $242 billion in 2017, 16th largest amongst metro areas in the United States.
El Paso–Juárez, also known as Juárez–El Paso, the Borderplex or Paso del Norte, is a binational metropolitan area, or conurbation, on the border between Mexico and the United States. The region is centered on two large cities: Ciudad Juárez, Chihuahua, Mexico and El Paso, Texas, U.S. Additionally, nearby Las Cruces, New Mexico, U.S. is sometimes included as part of the region, referred to as El Paso–Juárez–Las Cruces or El Paso–Juárez–Southern New Mexico. With over 2.7 million people, this binational region is the 2nd largest metropolitan area on the United States–Mexico border. The El Paso–Juárez region is the largest bilingual, binational work force in the Western Hemisphere.
Only one Canadian province is fully contained in the Mountain Time Zone:
One province and one territory are split between the Mountain Time Zone and the Pacific 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.
British Columbia is the westernmost province of Canada, located between the Pacific Ocean and the Rocky Mountains. With an estimated population of 5.016 million as of 2018, it is Canada's third-most populous province.
The Northwest Territories is a federal territory of Canada. At a land area of approximately 1,144,000 km2 (442,000 sq mi) and a 2016 census population of 41,786, it is the second-largest and the most populous of the three territories in Northern Canada. Its estimated population as of 2018 is 44,445. Yellowknife became the territorial capital in 1967, following recommendations by the Carrothers Commission.
The townsite of Tungsten is located at Cantung Mine in the Northwest Territories. It is accessible from Watson Lake, Yukon. Tungsten was built in 1961 and the tungsten mine went into operation in 1962 as a large open pit mine in the Mackenzie Mountains. It originally consisted of several small bungalow houses. Total population of Tungsten during the 1960s was approximately 120 persons, including about 27 families. In 1968 families were housed in 28 units.
One territory and one province are split between the Mountain Time Zone and the Central Time Zone
The following states have the same time as Mountain Time Zone:
Five states are fully contained in the Mountain Time Zone:
Four states are split between the Mountain Time Zone and the Pacific Time Zone. The following locations observe Mountain Time:
Six states are split between the Mountain Time Zone and the Central Time Zone. The following locations observe Mountain Time:
A time zone is a region of the globe that observes a uniform standard time for legal, commercial, and social purposes. Time zones tend to follow the boundaries of countries and their subdivisions because it is convenient for areas in close commercial or other communication to keep the same time.
The history of standard time in the United States began November 18, 1883, when United States and Canadian railroads instituted standard time in time zones. Before then, time of day was a local matter, and most cities and towns used some form of local solar time, maintained by some well-known clock. The new standard time system was not immediately embraced by all.
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.
The Eastern Time Zone (ET) is a time zone encompassing part or all of 22 states in the eastern part of the contiguous United States, parts of eastern Canada, the state of Quintana Roo in Mexico, Panama in Central America, and the Caribbean Islands.
Time in the United States, by law, is divided into nine standard time zones covering the states and its possessions, with most of the United States 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. Official and highly precise timekeeping services (clocks) are provided by two federal agencies: the National Institute of Standards and Technology (NIST) ; and its military counterpart, 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.
The Uniform Time Act of 1966, Pub.L. 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.
UTC−05:00 is a time offset that subtracts five hours from Coordinated Universal Time (UTC). In North America, it is observed in the Eastern Time Zone during standard time, and in the Central Time Zone during the other eight months. The western Caribbean uses it year round.
The Atlantic Time Zone is a geographical region that keeps standard time—called Atlantic Standard Time (AST)—by subtracting four hours from Coordinated Universal Time (UTC), resulting in UTC−04:00. During part of the year, some portions of the zone observe daylight saving time, referred to as Atlantic Daylight Time (ADT), by moving their clocks forward one hour to result in UTC−03:00. The clock time in this zone is based on the mean solar time of the 60th meridian west of the Greenwich Observatory.
UTC−07:00 is a time offset that subtracts 7 hours from Coordinated Universal Time (UTC). In North America, it is observed in the Mountain Time Zone during standard time, and in the Pacific Time Zone during the other 8 months. A few places use it year-round.
UTC−06:00 is a time offset that subtracts six hours from Coordinated Universal Time (UTC). 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.
Canada is divided into six time zones, based on proposals by Scottish Canadian railway engineer Sir Sandford Fleming, who pioneered the use of the 24-hour clock, the world's time zone system, and a standard prime meridian. Most of Canada operates on standard time from the first Sunday in November to the second Sunday in March and daylight saving time the rest of the year.
Tarkio is an unincorporated community in Montana, located in Mineral County. Tarkio falls in Mountain Time Zone (MST/MDT) and observes daylight saving time.
The Chamorro Time Zone, formerly the Guam Time Zone, is a United States time zone which observes standard time ten hours ahead of Coordinated Universal Time (UTC+10:00). The clock time in this zone is based on the mean solar time of the 150th meridian east of the Greenwich Observatory.
Mexico uses four main time zones since February 2015. Most of the country observes Daylight Saving Time.
Daylight saving time in the United States is the practice of setting the clock forward by one hour during the warmer part of the year, so that evenings have more daylight and mornings have less. Most areas of the United States observe daylight saving time (DST), the exceptions being Arizona, Hawaii, and the overseas territories of American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the United States Virgin Islands. The Uniform Time Act of 1966 established the system of uniform Daylight Saving Time throughout the US.
Milner is an unincorporated community located in Routt County, Colorado, United States. The elevation is 6,522 feet above sea level. Milner lies in the Mountain Time Zone (MST/MDT) and observes daylight saving time. The settlement is located along State Hwy 40 between the nearby communities of Craig and Steamboat Springs.
The Standard Time Act of 1918, also known as the Calder Act, was the first United States federal law implementing Standard time and Daylight saving time in the United States. It authorized the Interstate Commerce Commission to define each time zone.
Daylight saving time (DST) is observed in all ten Canadian provinces and three territories. However, there are exceptions within several provinces and the territory of Nunavut, including most of Saskatchewan, which observes Central Standard Time year-round even though the province is in the Mountain Zone, effectively putting it on DST year-round. Under the Canadian Constitution, laws related to timekeeping are a purely provincial or territorial matter.
Time in Arizona, as in all US states, is regulated by the United States Department of Transportation.
Time zones in North America
|Time zone||Hours from UTC: Standard time||Hours from UTC: Daylight saving time|
|Hawaii–Aleutian (in Hawaii)||–10||–10|
|Hawaii–Aleutian (in Alaska)||–10||–9|
|Pacific (in Alaska)||–8||–8|
|Pacific (other states/provinces)||–8||–7|
|Mountain (Arizona, Sonora, and Northeastern British Columbia only)||–7||–7|
|Mountain (other states/provinces)||–7||–6|
|Central (Saskatchewan only)||–6||–6|
|Central (other states/provinces)||–6||–5|
|Eastern (parts of Nunavut and the Caribbean)||–5||–5|
|Eastern (other states/provinces)||–5||–4|
|Atlantic (Natashquan River)||–4||–4|
|Atlantic (other states/provinces)||–4||–3|
| Saint Pierre and Miquelon |
and most of Greenland