Mountain Time Area Codes

What the Mountain Time zone covers

The Mountain Time zone includes Arizona, Colorado, Idaho, Montana, New Mexico, Texas, Utah, Wyoming. Mountain Time covers the Rockies and high desert, from Montana down to New Mexico and across to Arizona.

UTC offset and daylight saving

This zone runs at UTC−7 in winter (MST) and UTC−6 in summer (MDT). It mostly observes daylight saving time. Most of Arizona stays on Mountain Standard Time year-round and does not change clocks, so in summer it matches Pacific Time.

Best time to call this zone

Standard business hours (9 a.m. to 5 p.m.) in this zone are when you're most likely to reach an office or store. Most of Arizona stays on Mountain Standard Time year-round and does not change clocks, so in summer it matches Pacific Time. If you only have a phone number, our phone number finder tells you which zone it belongs to.