|Mountain Time Zone|
|04:35, September 28, 2021 MST |
05:35, September 28, 2021 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 (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.
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 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.
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 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.
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:
One territory and one province are split between the Mountain Time Zone and the Central 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.
The following states have the same time as Mountain Time Zone:
Six states are fully contained in the Mountain Time Zone:
Two 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:
The following is a list of major cities located within the Mountain Time Zone, ordered alphabetically.
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 23 states in the eastern part of the United States, parts of eastern Canada, the state of Quintana Roo in Mexico, Panama and Colombia, mainland Ecuador, Peru, and a small portion of westernmost Brazil in South America, along with certain Caribbean and Atlantic islands.
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.
Time in the United States, by law, is divided into nine standard time zones covering the states, territories and other US 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 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.
UTC−05:00 is an identifier for a time offset from UTC of −05:00. 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.
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.
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.
Canada is divided into six time zones, based on proposals by Scottish Canadian railway engineer 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.
Hymenoxys is a genus of plants in the sunflower family, native to North and South America. It was named by Alexandre Henri Gabriel de Cassini in 1828.
Tarkio is an unincorporated community in Montana, United States, 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 (DST).
Cirsium arizonicum, the Arizona thistle, is a North American species of thistle in the sunflower family, native to the southwestern United States and northwestern Mexico. It has been found in Arizona, southeastern California, New Mexico, Nevada, Colorado, Utah, Sonora, and northwestern Chihuahua.
Platanus wrightii, the Arizona sycamore, is a sycamore tree native to Arizona and New Mexico with its range extending south into the Mexican states of Sonora, Chihuahua, and Sinaloa.
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.
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 U.S. Hwy 40 between the nearby communities of Craig and Steamboat Springs.
Mexico adopted daylight saving time nationwide in 1996, even in its tropical regions, because of its increasing economic ties to the United States. Although the United States changed the schedule for DST beginning in 2007, only the municipalities located less than 20 km from the border have adopted the change. Daylight saving time for Mexico begins the first Sunday of April and ends last Sunday of October; and is usually referred to as the "Summer Schedule".
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.
Coalwood is an unincorporated community in northern Powder River County, Montana, United States. It lies along Montana Highway 59, 23.5 miles (37.8 km) north of the town of Broadus, the county seat of Powder River County.
|Time zone||Hours from UTC: Standard time||Hours from UTC: Daylight saving time|
|Hawaii–Aleutian (in Hawaii)||−10||−10|
|Hawaii–Aleutian (parts of Alaska)||−10||−9|
|Pacific (parts of Alaska)||−8||−8|
|Pacific (other states/provinces)||−8||−7|
|Mountain (Arizona, Sonora, Yukon, and Northeastern British Columbia only)||−7||−7|
|Mountain (other states/provinces)||−7||−6|
|Central (other states/provinces)||−6||−5|
|Eastern (parts of Nunavut, Ontario, 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