What is the difference between MDT and UTC?
MDT is 6 hours behind UTC. MDT (Mountain Daylight Time) is used during Daylight Saving Time in the Mountain time zone, typically from March to November.
UTC time
MDT
Mountain Daylight Time
6 Jan 2026
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Frequently Asked Questions
Does this area observe DST?
MDT itself is the daylight saving time version of MST. MDT is observed from the second Sunday in March to the first Sunday in November in most areas, when the region switches back to MST (Mountain Standard Time, UTC-7:00). Note that Arizona does not observe DST and remains on MST year-round.
Which major cities follow this pattern?
Cities such as Denver, Salt Lake City, Albuquerque, and Calgary follow MDT during the summer months. Phoenix, Arizona remains on MST year-round.
What areas share the same hours?
Parts of the Mountain United States (Colorado, Utah, New Mexico, Montana, Wyoming) and Canada (Alberta, parts of British Columbia) observe MDT during daylight saving time.
How does this compare with MST?
MDT is 1 hour ahead of MST. MDT (UTC-6:00) is used during summer months, while MST (UTC-7:00) is used during winter months.
Why does this area observe DST?
Daylight saving time is observed to make better use of daylight during the longer summer days, potentially reducing energy consumption and allowing for more evening activities. However, Arizona opts out due to extreme summer heat.
How did this system get established?
MDT was established as part of the daylight saving time system adopted in the United States and Canada, beginning in the early 20th century to conserve energy during World War I.
What are the typical work hours here?
Work hours in areas following MDT are generally from 8:00 AM to 5:00 PM, with a lunch break in the middle of the day.
What is the economic importance of this area?
The Mountain region includes significant industries such as mining, energy, technology, and tourism, with hubs in cities like Denver, Salt Lake City, and Calgary.