Why does Arizona observe MST year-round?

Arizona opted out of Daylight Saving Time in 1968 to reduce evening energy consumption for air conditioning, keeping Phoenix, Tucson, and Scottsdale on permanent MST (UTC-7) all year.

When do other Mountain states observe MST?

States like Colorado, Utah, and New Mexico observe MST during winter months (November to March), advancing to Mountain Daylight Time (MDT, UTC-6) in summer.

Is MST ever the same time as California?

Yes. During the summer, when California observes Pacific Daylight Time (PDT, UTC-7), Arizona and California share the exact same clock reading.

Why does Arizona observe MST year-round?

Arizona opted out of Daylight Saving Time in 1968 to reduce evening energy consumption for air conditioning, keeping Phoenix, Tucson, and Scottsdale on permanent MST (UTC-7) all year.

When do other Mountain states observe MST?

States like Colorado, Utah, and New Mexico observe MST during winter months (November to March), advancing to Mountain Daylight Time (MDT, UTC-6) in summer.

Is MST ever the same time as California?

Yes. During the summer, when California observes Pacific Daylight Time (PDT, UTC-7), Arizona and California share the exact same clock reading.

UTC -7MSTDST Active (Summer Time)

Mountain Standard Time (MST) Clock

What time is it in MST right now? Live Mountain Standard Time clock with seconds, UTC-7 offset, Arizona permanent time rules, and Rocky Mountain cities.

10:23:31 AMMDT

Saturday, October 10, 2026

Day 283 of 2026 • Week 41

Your location vs this zone: 6 hours behind.

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Live Mountain Standard Time (UTC-7) Display

Mountain Standard Time (MST, UTC-7) anchors the Intermountain West of North America. Covering major tech, aerospace, and research centers in Arizona, Colorado, Utah, and Alberta, MST connects the Great Plains with the Pacific Coast.

Because Arizona maintains permanent MST year-round while neighboring states alternate with daylight saving time, tracking local offsets requires attention. Use our live clock to confirm current Mountain civil time with verified atomic precision.

Arizona's Year-Round Standard Time Policy

Observances, offset conventions, and international coordination for Mountain Standard Time (MST).

Rocky Mountain Cities and Research Laboratories

Observances, offset conventions, and international coordination for Mountain Standard Time (MST).

Timezone Specifications & Offset Anchors

Civil OffsetUTC -7

Primary IANA IDAmerica/Denver

Daylight SavingObserves Seasonal DST

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Frequently Asked Questions: Mountain Standard Time (MST) Clock

Common queries, time calculations, and scientific explanations

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Mountain Standard Time (MST) is the civil time zone observed across the Rocky Mountain region, anchored to an offset of UTC-7 (7 hours behind Coordinated Universal Time).