Time zone · Americas
MDT
Mountain Daylight Time
Mountain Daylight Time stretches from the Rockies of the United States deep into western Canada and northern Mexico, putting about six cities under one hour—right now, Boise, Denver, Edmonton, and their neighbors sit a step ahead of clock-ticking world events. When summer calls, the whole region springs forward together, trading the crisp, early mountain darkness for longer golden evenings that stretch across borders.
Friday, June 5, 2026
Current offset
UTC-06:00
Daylight · MDT
Daylight saving
Active
Reverts 1 Nov 2026
IANA zones
6
6 observe DST, 0 don't
DST offset
—
No summer variant
About MDT
Standard time, with a summer shift.
Mountain Daylight Time stretches from the Rockies of the United States deep into western Canada and northern Mexico, putting about six cities under one hour—right now, Boise, Denver, Edmonton, and their neighbors sit a step ahead of clock-ticking world events. When summer calls, the whole region springs forward together, trading the crisp, early mountain darkness for longer golden evenings that stretch across borders.
IANA zones · the technical identifiers
The 6 zones that resolve to MDT.
For software, always store the IANA identifier — never the abbreviation alone. The database keeps these zones distinct because their rules can, and historically did, diverge.
Cities currently on MDT
The same hour, city by city.
6 cities · all UTC-06:00
Where MDT is used
3 countries.
Same offset · UTC-06:00
Other zones at UTC-06:00 right now.
These named zones share MDT's offset today. When daylight saving rules differ, they drift apart for part of the year.
Frequently asked questions
Common questions about MDT, daylight saving, and how to handle it in software. Can't find what you need? Email [email protected].
- Why does Mountain Daylight Time apply to places in three different countries?
- Mountain Daylight Time covers parts of the United States, Canada, and Mexico because all three nations share the same longitudinal band across the Rocky Mountains. Cities like Denver, Edmonton, and Ciudad Juárez all fall within the same UTC-6 offset during the summer months.
- What makes Mountain Daylight Time unique among North American time zones?
- MDT is one of the few daylight saving time offsets that spans three countries, uniting parts of the U.S., Canadian, and Mexican mountain regions under a single UTC-6 offset from March through October.
- How does daylight saving time affect daily life in the Mountain region?
- When clocks spring forward, cities like Boise and Denver gain an extra hour of evening sunlight, which residents take advantage of for hiking, outdoor dining, and other mountain activities before the short winter days return.
- Why was UTC-06:00 chosen for Mountain Daylight Time?
- UTC-06:00 reflects the mean solar time for the longitudinal band running through the Rocky Mountain region. It aligns cities like Denver and Edmonton with their natural daylight patterns during the summer months.
- How does Mountain Daylight Time compare to Pacific Daylight Time?
- Mountain Daylight Time is one hour ahead of Pacific Daylight Time (PDT). When it's noon in Los Angeles, it's already 1 PM in Boise and Denver, giving mountain states a head start on the day's business.
- When does Mountain Standard Time resume?
- On the first Sunday of November, the clocks fall back from MDT to Mountain Standard Time (MST), returning the region to UTC-07:00 and marking the end of the long summer daylight hours.
- Are there any major cities in the Mountain Time Zone?
- Denver, Colorado, is the largest city in the Mountain Time Zone, followed by Edmonton, Alberta. Both cities serve as major business hubs that coordinate across the MDT offset during summer months.
Free · Developer API
Time, as JSON.
Every IANA time zone with live offsets, DST status, and the countries and cities that use them — clean, dependable JSON. Sign up free and get an API key in seconds.
countries, cities, convert, DST transitions coming next.
Get your free API key →