MST vs MDT: what's the difference?
Denver (Mountain Time) right now: --:-- () ·
Phoenix, Arizona right now: --:-- () ·
MST is Mountain Standard Time, UTC−7, used in winter. MDT is Mountain Daylight Time, UTC−6, used during daylight saving time (second Sunday in March to the first Sunday in November). Arizona is the big exception: it stays on MST all year.
| MST | MDT | |
|---|---|---|
| Full name | Mountain Standard Time | Mountain Daylight Time |
| UTC offset | UTC−7 | UTC−6 |
| When | Early November to mid-March, and all year in Arizona | Mid-March to early November |
| Example cities | Phoenix (all year), Denver in winter | Denver, Salt Lake City, Albuquerque, Boise in summer |
More: Mountain Time Zone · Mountain vs Eastern time · time in Denver
Questions people ask
What is the difference between MST and MDT?
MST (Mountain Standard Time) is UTC−7 and is used in winter. MDT (Mountain Daylight Time) is UTC−6 and is used during daylight saving time, from the second Sunday in March to the first Sunday in November.
Is Denver on Mountain Time?
Yes. Denver, and all of Colorado, is on Mountain Time. It uses MST in winter and MDT in summer.
Does Arizona use MST or MDT?
Arizona stays on MST (UTC−7) all year and does not change its clocks. The exception is the Navajo Nation in northeastern Arizona, which does observe daylight saving time. So in summer, Phoenix has the same time as Los Angeles; in winter, the same time as Denver.
Which states are on Mountain Time?
Colorado, Montana, New Mexico, Utah and Wyoming, most of Idaho, and parts of Kansas, Nebraska, North Dakota, South Dakota, Oregon and Texas. Arizona is on Mountain Standard Time all year.