The only province in Canada to be fully covered by MST is Alberta whereas other provinces like British Columbia and Northwest Territories are split between MST and PST. Mountain Time is observed in parts of Canada, the US and Mexico. In Mexico, this time zone is known as Zona Pacifico (Pacific Zone). The name Mountain Time comes from it covering the Rocky Mountains in Western United States. It is 7 hours behind UTC and turns into MDT in the summer. Mountain Standard Time is observed in the Western part of central US and Canada, as well as the North West corner of Mexico. DST is in effect between March and November and adds one hour time difference to UTC.
![mdt vs mst mdt vs mst](https://image.slidesharecdn.com/whats-new-in-mdt-1226675351756373-8/95/whats-new-in-mdt-29-728.jpg)
MDT is observed in almost all locations that observe Mountain Time, except the states of Arizona (US) and Sinaloa (Mexico). The largest city observing Mountain Daylight Time is Phoenix, followed by Denver and El Paso/Juarez. In Mexico, it is only the states in the north western corner of the country, including Baja California, Sinaloa and Chihuahua that observe MDT. The only province in Canada to be fully covered by MDT is Alberta whereas other provinces like British Columbia and Northwest Territories are split between MDT and PDT. MDT is observed in parts of Canada, the US and Mexico. In the US, Arizona, Colorado, Montana, Utah, New Mexico and Wyoming are all observing Mountain Daylight Time but there is also a bunch where part of the state observe MDT and part another time zone, like CDT or PDT. Countries observing Mountain Daylight Time: The name Mountain Daylight Time comes from it covering the Rocky Mountains in Western United States. It is 6 hours behind UTC and turns into MST in the summer.
![mdt vs mst mdt vs mst](https://i.ytimg.com/vi/ad1yeIGrSjU/hqdefault.jpg)
MDT is observed in the Western part of central US and Canada, as well as the North West corner of Mexico.