What UTC offset does the Mountain Time Zone use?
The Mountain Time Zone runs UTC-7 as Mountain Standard Time and UTC-6 as Mountain Daylight Time. Its clock is based on the mean solar time of the 105th meridian west of the Greenwich Observatory.
Questions about Mountain Time Zone
Short answers, pulled from the story.
When did Yukon switch to year-round Mountain Standard Time in the Mountain Time Zone?
Yukon switched to Mountain Standard Time year-round on the 24th of September 2020. Before that date, the territory used the Pacific Time Zone, running UTC-8 in winter and UTC-7 in summer.
Which city is the largest in the Mountain Time Zone?
Phoenix, Arizona, is the largest city in the Mountain Time Zone, and the Phoenix metropolitan area is the zone's largest metropolitan area. Juárez, Chihuahua, Mexico, is the largest city in the zone that observes daylight saving time.
Which US states lie entirely within the Mountain Time Zone?
Six US states are entirely within the Mountain Time Zone: Colorado, Montana, New Mexico, Utah, Wyoming, and Arizona. Arizona does not observe daylight saving time, except on the Navajo Nation.
Does Mexico still observe daylight saving time in the Mountain Time Zone?
Most of Mexico abandoned daylight saving time on the 30th of October 2022. Exceptions remain in Chihuahua's northwestern border municipalities of Janos, Ascensión, Juárez, Guadalupe, and Práxedis Gilberto Guerrero, which still observe it.
How did British Columbia's clocks change within the Mountain Time Zone in 2026?
On the 8th of March 2026, most of British Columbia adopted UTC-7 year-round while continuing to call its time zone Pacific Time. Southeastern parts of the province near the Alberta border still observe daylight saving time, shifting between UTC-6 in summer and UTC-7 in winter.