Current Time in IANA US/Mountain Timezone
IANA Name: US/Mountain
Standard Offset: UTC −07:00
Daylight Saving: Yes
DST Offset: UTC −06:00
DST Abbreviation: MDT
Currently Observing DST: Yes ✅
US/Mountain Time Zone: A Comprehensive Guide
The US/Mountain time zone is a canonical IANA time zone identifier representing the Mountain Time Zone in the United States. It observes Mountain Standard Time (MST) at UTC-07:00 during standard time and Mountain Daylight Time (MDT) at UTC-06:00 during daylight saving time. This zone covers a vast region of the western United States and parts of Canada and Mexico, with its anchor city being Denver, Colorado.
Geographic Coverage and Users
The US/Mountain time zone applies to the entire states of Colorado, Montana, New Mexico, Utah, and Wyoming, as well as the western portions of Kansas, Nebraska, South Dakota, and Texas. It also includes the Navajo Nation (which observes DST) and the Mountain Standard Time portion of Arizona (which does not observe DST, but the Navajo Nation does). Major cities in this zone include Denver, Salt Lake City, Albuquerque, Phoenix (Arizona is on MST year-round except Navajo Nation), El Paso (Texas), and Billings. In Canada, the zone covers Alberta, most of Saskatchewan (except for areas on Central Time), and parts of British Columbia and the Northwest Territories. In Mexico, it covers the states of Baja California Sur, Chihuahua (except the border towns), Nayarit (most), Sinaloa, and Sonora. The zone is used by approximately 15 million people in the United States alone.
Offset and Abbreviation Meaning
During standard time, the offset is UTC-07:00, abbreviated as MST (Mountain Standard Time). When daylight saving time is in effect, the offset shifts to UTC-06:00, abbreviated as MDT (Mountain Daylight Time). The abbreviation MST has been in use since the early 20th century and is derived from the Rocky Mountain region. The offset is exactly seven hours behind Coordinated Universal Time, meaning that when it is noon UTC, it is 5:00 AM MST or 6:00 AM MDT.
Daylight Saving Time Behavior
US/Mountain observes daylight saving time (DST) except for the state of Arizona (excluding the Navajo Nation) and the Mexican state of Sonora. DST begins on the second Sunday of March at 2:00 AM MST, when clocks spring forward to 3:00 AM MDT. It ends on the first Sunday of November at 2:00 AM MDT, when clocks fall back to 1:00 AM MST. Recent and upcoming DST change dates include: March 9, 2025 (to MDT), November 2, 2025 (to MST), March 8, 2026 (to MDT), and November 1, 2026 (to MST). The yearly rhythm means that from early March to early November, the zone is on MDT, and for the remaining four months, it is on MST. This pattern aligns with the rest of the United States that observes DST.
Main Countries and Cities
- United States: Denver (Colorado), Salt Lake City (Utah), Albuquerque (New Mexico), Phoenix (Arizona, MST year-round), El Paso (Texas), Billings (Montana), Cheyenne (Wyoming), Colorado Springs (Colorado), Provo (Utah), Tucson (Arizona, MST year-round)
- Canada: Calgary (Alberta), Edmonton (Alberta), Saskatoon (Saskatchewan, most on CST but some areas on MST), Yellowknife (Northwest Territories), Fort McMurray (Alberta)
- Mexico: Chihuahua (Chihuahua), Hermosillo (Sonora), Mazatlan (Sinaloa), La Paz (Baja California Sur)
Practical Guidance for Scheduling
When scheduling calls or meetings across time zones, note that US/Mountain is typically 2 hours behind Eastern Time (ET), 1 hour behind Central Time (CT), and 1 hour ahead of Pacific Time (PT) during standard time. During DST, these offsets remain the same because all zones shift together. For international calls, US/Mountain is 7 or 8 hours behind UTC. For example, 9:00 AM MDT is 15:00 UTC. Common business hours overlap: 9:00 AM to 5:00 PM Mountain Time corresponds to 11:00 AM to 7:00 PM Eastern Time, 10:00 AM to 6:00 PM Central Time, and 8:00 AM to 4:00 PM Pacific Time. For Europe, 9:00 AM MDT is 5:00 PM Central European Summer Time (CEST), providing a narrow overlap of 9:00 AM to 11:00 AM MDT (5:00 PM to 7:00 PM CEST). In Asia, 9:00 AM MDT is 11:00 PM China Standard Time, making scheduling difficult. Always confirm the DST status of the other party, as some regions (like Arizona) may not observe DST.
Frequently Asked Questions
What is the current time in US/Mountain?
The current time depends on the date. During standard time (early November to early March), it is UTC-07:00 (MST). During daylight saving time (early March to early November), it is UTC-06:00 (MDT). You can check a world clock for the exact time.
Does all of Arizona observe Mountain Standard Time without DST?
Most of Arizona does not observe daylight saving time and remains on MST year-round. However, the Navajo Nation, which extends into Arizona, does observe DST. So parts of Arizona may be on MDT during summer.
What is the difference between US/Mountain and America/Denver?
US/Mountain is a canonical IANA time zone identifier that is equivalent to America/Denver. Both represent the Mountain Time Zone in the United States. America/Denver is the preferred name, but US/Mountain is an alias for convenience.
How do I convert Mountain Time to my local time?
Determine if the Mountain region is on MST (UTC-07:00) or MDT (UTC-06:00). Then calculate the offset from your local time zone. For example, if you are in New York (Eastern Time, UTC-05:00 standard, UTC-04:00 DST), Mountain Time is 2 hours behind during both standard and DST.
Why is the zone called Mountain?
The name comes from the Rocky Mountain range, which runs through the region. The time zone was originally called Mountain Time because it covered the mountainous areas of the western United States and Canada.
What is the IANA time zone ID for Mountain Time in Canada?
For most of Canada's Mountain Time region, the IANA zone is America/Edmonton (for Alberta) or America/Cambridge_Bay (for parts of Nunavut). US/Mountain is primarily for the United States, but it can be used for consistency across the entire Mountain Time Zone.