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America/Denver

America/Denver is the IANA time zone for Mountain (most areas) in the United States.

UTC−06:00

Tue, Sep 29 UTC−6 MDT

Offsets and daylight saving time

Standard offset
UTC−07:00
Daylight offset
UTC−06:00
Rule
Daylight saving time from the second Sunday in March at 02:00 to the first Sunday in November at 02:00 (local time).

Next clock changes

  • Sunday, November 1, 2026 at 02:00: back to UTC−7 (MDT → MST)
  • Sunday, March 14, 2027 at 02:00: forward to UTC−6 (MST → MDT)

Names

Generic name
Mountain Time
Abbreviation
MST / MDT
Standard / daylight
Mountain Standard Time / Mountain Daylight Time
Aliases
America/Shiprock, MST7MDT, Navajo and US/Mountain (old ids that resolve to America/Denver)

Use it in code

// JavaScript
new Intl.DateTimeFormat('en-US', { timeZone: 'America/Denver' })

# Python
from zoneinfo import ZoneInfo
ZoneInfo('America/Denver')

-- PostgreSQL
SELECT now() AT TIME ZONE 'America/Denver';

Cities in America/Denver

Also in this zone: El Paso, Albuquerque, Colorado Springs, Aurora, Salt Lake City, Fort Collins, Lakewood, West Valley City, Thornton, Billings, Westminster, Arvada, Provo, West Jordan, Centennial, Pueblo, Greeley.

Offset history since 1970

  • 1970–2026: UTC−7 and UTC−6 each year

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