Mountain Time (MST/MDT)

What is Mountain Time?

Mountain Time (MT) is the name of a time zone which is seven hours (GMT-7) behind Greenwich Mean Time (GMT).

It is one of the main USA time zones, referred to as Mountain Standard Time or MST. Mountain Time used as well in Canada and parts of western Mexico.

Every year, once clocks go forward by an hour, at the beginning of Daylight Saving Time (DST), the time difference becomes 6 hours behind GMT (GMT-6). During the DST period, this time zone is known as Mountain Daylight Time or MDT. When clocks go back, MDT reverts to MST.

Arizona is one notable exception from the DST rule, among the states that use Mountain Time. Apart from the Navajo Nation, in the northeastern part of the state, Arizona stays on Mountain Standard Time all year round.

Cities on Mountain Time Zone

• Phoenix (Arizona), no DST
• El Paso (Texas)
• Denver (Colorado)
• Boise (Idaho)
• Salt Lake City (Utah)