Back Noord-Amerikaanse Bergtydsone Afrikaans المنطقة الزمنية الجبلية Arabic Tiempo de la montaña Spanish منطقه زمانی کوهستانی Persian Kalliovuorten aika Finnish Heure des Rocheuses French Mountain Time Zone Hungarian Waktu Standar Pegunungan ID Fjallatími Icelandic 山岳部標準時 Japanese
| Mountain Time Zone | |
|---|---|
| Time zone | |
 Mountain Time Zone | |
| UTC offset | |
| MST | UTC−07:00 |
| MDT | UTC−06:00 |
| Current time | |
| 00:54, November 18, 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.[a]
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.
Baja California Sur, Sinaloa and 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.
- ^ "49 CFR 71.8 Mountain zone". Code of Federal Regulations. Retrieved October 7, 2011.
- ^ "49 CFR 71.7 Boundary line between central and mountain zones". Code of Federal Regulations. Retrieved October 7, 2011.
- ^ "49 CFR 71.9 Boundary line between mountain and Pacific zones". Code of Federal Regulations. Retrieved October 7, 2011.
- ^ Robbins, Ted (March 11, 2007). "Arizona Says No to Daylight-Saving Time". Weekend Edition Sunday. National Public Radio. Retrieved June 18, 2012.
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