MST Time Zone Converter

What MST means

Mountain Standard Time is UTC−7. The canonical zone in the IANA database is America/Denver, which covers Colorado, Wyoming, Montana, most of New Mexico, Alberta and Saskatchewan's western neighbour — plus the Navajo Nation, which follows Mountain Time and observes daylight saving even though the surrounding Arizona does not.

For part of the year Mountain Time is called Mountain Daylight Time (MDT) at UTC−6, between the second Sunday in March and the first Sunday in November. Outside that window it is MST at UTC−7. The abbreviation and the offset always travel together, and this converter shows both.

The exception that catches everyone: Phoenix

Arizona does not observe daylight saving. Phoenix, Tucson and most of the state stay on MST (UTC−7) all year, so during the summer they sit on the same clock as Los Angeles even though they are two time zones east. In July, 09:00 in Phoenix is 09:00 in Los Angeles, while 09:00 in Denver is 10:00.

Hermosillo in Mexico also keeps MST year round, and Ciudad Juárez — which shares a border with El Paso — moved from Mountain Time to Central Time in 2022, so it now observes MDT in summer and CST in winter like Texas. The border between these rules runs straight through a city, which is why tools that guess from geography get it wrong and tools that read IANA rules do not.

Mountain Time against the other US zones

North America is unusually regular: the four main zones are exactly one hour apart, so Mountain Time sits in the middle. The catch is that only some of them observe daylight saving, and they do not all switch on the same date.

• MT → Pacific Time (Los Angeles, Seattle): 1 hour ahead
• MT → Central Time (Chicago, Mexico City): 2 hours ahead
• MT → Eastern Time (New York, Toronto): 3 hours ahead
• MT → London in winter: 7 hours ahead · in summer: 6 hours ahead
• MT → Berlin in winter: 8 hours ahead · in summer: 7 hours ahead
• MT → Dubai: 11 hours ahead · Sydney: 17 hours ahead
• MT → Tokyo: 18 hours ahead — the next calendar day

When Mountain Daylight Time runs

MDT starts on the second Sunday in March, when clocks jump from 02:00 to 03:00 local, and ends on the first Sunday in November, when they fall back from 02:00 to 01:00. It covers roughly 26 weeks of the year.

This matters more for Mountain Time than for most zones because of its neighbours: because Phoenix and Hermosillo never move, the practical gap between Denver and Phoenix changes from one hour to two in March and back again in November. Any recurring meeting that crosses the Rockies needs its recurring rule re-checked twice a year, not once.