Mountain Daylight Time (MDT) is 6 hours behind Coordinated Universal Time (UTC). This time zone is in use during Daylight Saving Time in: North America.
See full time zone mapWhat Is Mountain Daylight Time?
Mountain Daylight Time is the second westernmost time zone in the United States and Canada. It is also used in Mexico.
It covers all or parts of 13 states in the US and five provinces or territories in Canada.
The MST time zone is the least populated time zone in the USA. It spans from northern Canada to Mexico.
In North America, Mountain Daylight Time shares a border with Central Daylight Time (CDT) in the east and with Pacific Daylight Time (PDT) in the west.
MDT or MST?
Mountain Daylight Time (MDT) is a North American time zone in use from the second Sunday in March to the first Sunday in November during Daylight Saving Time (DST). Mountain Standard Time (MST) is used during the remainder of the year.
MDT Is the Mountain Time Zone
In everyday usage, MDT is often referred to as Mountain Time (MT) or the Mountain Time Zone. This can add a bit of confusion as the term Mountain Time does not differentiate between standard time and Daylight Saving Time, so Mountain Time switches between MST and MDT in areas that use DST during part of the year.
Most North American time zones also have generic terms, including Pacific Time (PT), Central Time (CT), Eastern Time (ET), and Atlantic Time (AT).
Converting Mountain Time to Other US Time Zones
- Mountain Daylight Time (MDT) is 2 hours behind Eastern Daylight Time (EDT).
To convert MDT to EDT, you have to add two hours. - Mountain Daylight Time (MDT) is 1 hour behind Central Daylight Time (CDT).
To convert MDT to CDT, you have to add one hour. - Mountain Daylight Time (MDT) is 1 hour ahead of Pacific Daylight Time (PDT).
To convert MDT to PDT, you have to subtract one hour.
Where and When is MDT Observed?
North America
US states using MDT in the summer and MST in the winter
- Idaho - most of the state except western countiesBenewah, Bonner, Boundary, Clearwater, Kootenai, Latah, Lewis, Nez Perce, Shoshone and north part of Idaho
- Kansas - some western counties onlyGreeley, Hamilton, Sherman and Wallace
- Nebraska - western countiesArthur, Banner, Box Butte, Chase, Cheyenne, Dawes, Deuel, Dundy, Garden, Grant, Hooker, Keith, Kimball, Morrill, Perkins, Scotts Bluff, Sheridan, and Sioux and the western part of Cherry
- North Dakota - South-Western partscounties of Adams, Billings, Bowman, Golden Valley, Grant, Hettinger, Mercer, Slope and Stark, and southern parts of Dunn and McKenzie, most of Morton and Sioux counties
- South Dakota - western countiesBennett, Butte, Corson, Custer, Dewey, Fall River, Haakon, Harding, Jackson, Lawrence, Meade, Pennington, Perkins, Shannon, and Ziebach, and the western parts of Stanley
- Texas - a few counties in westEl Paso and Hudspeth and part of Culberson
Canadian provinces/territories using MDT in the summer and MST in the winter
- British Columbia - a few eastern communitiesCranbrook, Golden, Invermere