MDT time now (Mountain Daylight Time)
6:04AM
MDT · UTC−6
UTC−6−1 h vs New York (you)Denver now: MST, UTC−7
What MDT means
MDT stands for Mountain Daylight Time, UTC−6. It is used in the US and Canadian Rocky Mountain region.
It is a summer time: the daylight saving form of MST (UTC−7), one hour ahead. In Denver it applies from March to October/November: from the second Sunday of March at 2:00 AM to the first Sunday of November at 2:00 AM.
Who is on Mountain Standard Time all year
MST is UTC−7. Denver, Salt Lake City and Calgary’s old zone use it in winter and switch to MDT (UTC−6) in summer. Arizona, except the Navajo Nation, never switches, so Phoenix shows MST all year (NIST lists most of Arizona among the places without daylight saving time). Since 2020 Yukon and since 2026 British Columbia also keep UTC−7 permanently, and tzdata calls that MST.
Alberta also kept its summer clock: it moved to permanent UTC−6 on June 18, 2026, which tzdata labels CST from November 1, 2026. In winter Calgary is therefore an hour ahead of Denver and on the same time as Chicago.
Where and when MDT is used
4 zones use it for part of the year only, switching back to standard time in the other months. Computed from tzdata under the current rules.
| Main city | Time zone | Countries | When |
|---|---|---|---|
| Ciudad Juárez | America/Ciudad_Juarez | Mexico | March to November |
| Denver | America/Denver | United States | March to November |
| Boise | America/Boise | United States | March to November |
| Cambridge Bay | America/Cambridge_Bay | Canada | March to November |
How long MDT has been used
In the tzdata record, Denver has used MDT since 1918, Ciudad Juárez has used MDT since 1931 and Boise has used MDT since 1967.
MDT in the past
Zones whose tzdata history shows MDT before 2025 but that no longer use it:
- America/Edmonton (Calgary): 1918–2024
- America/Inuvik (Inuvik): 1979–2024
- America/Chihuahua (Chihuahua): 1931–2022
- America/Mazatlan (Culiacán): 1931–2022
- America/Ojinaga (Ojinaga): 1931–2022
- America/North_Dakota/Beulah (Beulah): 1918–2010
- America/Bahia_Banderas (Bahia Banderas): 1931–2009
- America/North_Dakota/New_Salem (New Salem): 1918–2003
- America/Hermosillo (Hermosillo): 1931–1998
- America/North_Dakota/Center (Center): 1918–1992
- America/Phoenix (Phoenix): 1918–1967
- America/Swift_Current (Swift Current): 1918–1961
MDT converted to other zones
Every column is a fixed offset, so this table is valid on any date. Remember that the regions behind some columns switch to summer time (EST to EDT, CET to CEST, GMT to BST); the clock in those cities is then an hour later than the column.
| MDT (UTC−6) | UTC (UTC+0) | EST (UTC−5) | PST (UTC−8) | CET (UTC+1) | IST (UTC+5:30) | JST (UTC+9) | AEST (UTC+10) |
|---|---|---|---|---|---|---|---|
| 12:00 AM | 6:00 AM | 1:00 AM | 10:00 PM (−1 day) | 7:00 AM | 11:30 AM | 3:00 PM | 4:00 PM |
| 6:00 AM | 12:00 PM | 7:00 AM | 4:00 AM | 1:00 PM | 5:30 PM | 9:00 PM | 10:00 PM |
| 9:00 AM | 3:00 PM | 10:00 AM | 7:00 AM | 4:00 PM | 8:30 PM | 12:00 AM (+1 day) | 1:00 AM (+1 day) |
| 12:00 PM | 6:00 PM | 1:00 PM | 10:00 AM | 7:00 PM | 11:30 PM | 3:00 AM (+1 day) | 4:00 AM (+1 day) |
| 3:00 PM | 9:00 PM | 4:00 PM | 1:00 PM | 10:00 PM | 2:30 AM (+1 day) | 6:00 AM (+1 day) | 7:00 AM (+1 day) |
| 6:00 PM | 12:00 AM (+1 day) | 7:00 PM | 4:00 PM | 1:00 AM (+1 day) | 5:30 AM (+1 day) | 9:00 AM (+1 day) | 10:00 AM (+1 day) |
| 9:00 PM | 3:00 AM (+1 day) | 10:00 PM | 7:00 PM | 4:00 AM (+1 day) | 8:30 AM (+1 day) | 12:00 PM (+1 day) | 1:00 PM (+1 day) |