CalendarHours
Home / Time Zones / Time Zone Abbreviations / Mountain Time Zone
Mountain Time • MST ↔ MDT • Live Zone Guide

Mountain Time Zone

Mountain Time (MT) uses Mountain Standard Time (MST), UTC−07:00, in standard time and Mountain Daylight Time (MDT), UTC−06:00, where daylight saving time is observed. On August 21, 2026, representative U.S. Mountain Time locations such as Denver are on MDT / UTC−06:00.

MT is the year-round zone family; MST and MDT are its seasonal forms. Do not label Denver, Salt Lake City, Albuquerque, Boise or Billings “MST” year-round. Use MT when the date is unspecified, and derive MST vs MDT from the date. The major U.S. exception is most of Arizona, which stays on MST / UTC−07:00 year-round.
Standard timeMST · UTC−07Mountain Standard Time
Daylight timeMDT · UTC−06Mountain Daylight Time
Representative IANAAmerica/DenverArizona uses America/Phoenix
Mountain Time Now Time Zone Converter Mountain Time Zone Map
Search MT, MST, MDT, Arizona, a city, an IANA zone, DST dates or a related time-zone reference.
Popular: MST Time Now MDT Time Now Time Zone Abbreviations Central Time Zone Time Zone Converter Mountain Time Zone Map

Mountain Time Zone at a Glance

Mountain Time is unusually easy to mislabel because seasonal Denver, fixed-MST Arizona and newly permanent UTC−06:00 Alberta can show the same clock at different times of year while following different rules.

MT

Mountain Time Now

See the live representative MT clock with the correct current MST or MDT abbreviation.

See live MT → MST

MST vs MDT

Understand UTC−07:00 standard time, UTC−06:00 daylight time and when each applies.

Compare MST & MDT → DST

2026 DST Dates

Seasonal U.S. Mountain Time locations changed March 8 and return November 1, 2026.

See 2026 changes → USA

U.S. Mountain Time States

See statewide MT/MST states, split-zone states and the Arizona–Navajo Nation exception.

See U.S. geography → IANA

Mountain Time IANA Zones

Learn why America/Denver and America/Phoenix represent different Mountain-zone behavior.

See IANA examples → AZ

Fixed MST vs Seasonal MT

See why Phoenix matches Denver in winter but Los Angeles in much of summer.

See Arizona's rule →

Mountain Time Now — MST or MDT?

The current abbreviation depends on the date and the location. This table uses America/Denver as the representative seasonal U.S. Mountain Time clock.

Browse time-zone abbreviations →
ReferenceIANA ZoneLive TimeCurrent AbbreviationCurrent UTC OffsetZone Family
Seasonal Mountain TimeAmerica/DenverLive——MT · MST ↔ MDT
Arizona referenceAmerica/PhoenixLive——MST fixed · no DST

Use MT for year-round, date-unspecified seasonal-zone references. Use MST for UTC−07:00 and MDT for UTC−06:00. Most of Arizona is legitimately MST all year.

Mountain Standard Time Mountain Daylight Time Convert Mountain Time

Mountain Time Reference Pages

Move between the MT family, seasonal abbreviations, neighboring U.S. zones, geographic current time and visual geography.

Parent ReferenceTime Zone AbbreviationsBrowse MT, MST, MDT and other global abbreviation families.→ Standard-Time FormMST Time NowMountain Standard Time is the fixed UTC−07:00 abbreviation.→ Daylight-Time FormMDT Time NowMountain Daylight Time is the UTC−06:00 seasonal abbreviation.→ Adjacent Seasonal ReferenceCDT Time NowCentral Daylight Time is one hour ahead of MDT.→ Neighboring U.S. ZonePacific Time ZoneRepresentative U.S. Pacific Time is normally one hour behind seasonal MT.→ Geographic DiscoveryWorld ClockFind current local time by city, state, country or location.→ Visual GeographyMountain Time Zone MapSee U.S. Mountain Time boundaries, split states and Arizona visually.→ ConversionTime Zone ConverterConvert MT for any date with MST/MDT applied automatically.→

Which U.S. States Are in the Mountain Time Zone?

The federal Mountain standard-time zone reaches all or part of 14 states. Six are wholly inside the Mountain zone; eight contain only a Mountain Time portion.

See all U.S. time zones →
CoverageStatesCurrent Practice
Mountain zone statewideArizona, Colorado, Montana, New Mexico, Utah, WyomingColorado, Montana, New Mexico, Utah and Wyoming use MST↔MDT; most of Arizona stays MST year-round
Split with Pacific TimeIdaho, Nevada, OregonMountain Time applies to southern/eastern Idaho, West Wendover in Nevada, and most of Malheur County in Oregon
Split with Central TimeKansas, Nebraska, North Dakota, South Dakota, TexasWestern portions use Mountain Time; eastern portions use Central Time

The federal Mountain zone lies between the Central–Mountain boundary in 49 CFR §71.7 and the Mountain–Pacific boundary in §71.9. The latter specifically carves West Wendover, Nevada into Mountain Time.

MT = MST ↔ MDT

Mountain Time Has Two Seasonal UTC Offsets

Mountain Standard Time (MST) is UTC−07:00. Mountain Daylight Time (MDT) is UTC−06:00. In U.S. Mountain Time locations that observe daylight saving time, the active clock changes on the second Sunday in March and the first Sunday in November. Arizona breaks the seasonal pattern.

MST Time Now MDT Time Now 2026 DST Dates Convert MT
DenverLive timeLoading current offset
PhoenixLive timeLoading current offset
Salt Lake CityLive timeLoading current offset
CalgaryLive timeLoading current offset

Mountain Time Difference from Central, Pacific, Eastern & Arizona

For representative U.S. zones following the same federal DST calendar, seasonal Mountain Time stays one hour behind Central and one hour ahead of Pacific Time. Arizona is the crucial exception.

Convert a specific date and time →
Reference Zone / CityTypical Relationship to Seasonal MTImportant Detail
Central TimeCT +1 hourRepresentative U.S. CT and MT locations change clocks on the same federal dates.
Pacific TimeMT +1 hourRepresentative U.S. seasonal MT remains one hour ahead of representative U.S. PT.
Eastern TimeET +2 hoursRepresentative U.S. ET and MT change clocks together.
Phoenix, ArizonaSame as Denver on MST; Phoenix −1h from Denver on MDTPhoenix stays UTC−07:00 while Denver advances to UTC−06:00.
Los AngelesDenver +1h year-roundSeasonal Denver and Los Angeles change on the same U.S. dates.
LondonLondon +7h on MST; +6h on MDTU.S. and U.K. transition dates create short seasonal mismatch windows.
Central Time Zone Pacific Time Zone Open Full Converter

Mountain Time Daylight Saving Time in 2026

Most U.S. Mountain Time locations follow the federal daylight-saving schedule. NIST confirms that in 2026 DST runs from March 8 at 2:00 AM local time until November 1 at 2:00 AM local time.

March 8, 2026 · 2:00 AM MSTSeasonal MT clocks jump forward to 3:00 AM MDT. UTC−07:00 becomes UTC−06:00.
November 1, 2026 · 2:00 AM MDTSeasonal MT clocks move back to 1:00 AM MST. UTC−06:00 becomes UTC−07:00.
General U.S. ruleSecond Sunday in March → first Sunday in November.

Arizona's Mountain Time Exception

NIST identifies Arizona as the major mainland-state exception to U.S. daylight saving time. Most of Arizona remains on MST / UTC−07:00 all year. The Navajo Nation does observe DST, so northeastern Arizona contains a real seasonal exception inside the state's fixed-MST pattern.

Phoenix, Tucson & most of ArizonaAmerica/Phoenix · MST · UTC−07:00 year-round.
Navajo NationObserves DST and switches MST ↔ MDT.
Summer consequencePhoenix matches Los Angeles on PDT and is one hour behind Denver on MDT.

Seasonal Mountain Time vs Fixed MST vs Alberta Time

The same UTC offset can represent different legal time systems. In 2026, that distinction became even more important across western North America.

Seasonal MT

Denver · America/Denver

Uses MST at UTC−07:00 in standard time and MDT at UTC−06:00 during U.S. daylight saving time.

Fixed MST

Phoenix · America/Phoenix

Most of Arizona remains on MST / UTC−07:00 year-round and does not follow Denver's seasonal clock changes.

Fixed UTC−07

Northeastern British Columbia

Communities such as Dawson Creek and Fort St. John continue observing a UTC−07:00 Mountain Standard Time-style clock year-round.

2026 Change

Alberta Time · UTC−06:00

Alberta historically used MST↔MDT but adopted permanent Alberta Time at UTC−06:00 in 2026 and will not return to MST in November.

Yukon

UTC−07:00 Year-Round

Yukon has used UTC−07:00 year-round since 2020, but it is legally Yukon Standard Time rather than seasonal U.S. Mountain Time.

Key Rule

Offset ≠ Complete Time-Zone Rule

Denver, Phoenix, Yukon and British Columbia can share an offset at times while following different legal systems and future behavior.

Quick Mountain Time Zone Compare

Compare representative seasonal Mountain Time with Arizona, neighboring U.S. zones and Alberta. The live tool applies each IANA location's current date-aware offset.

Live time
Current abbreviation, UTC offset and difference
⇄
Live time
Current abbreviation, UTC offset and difference
Open Full Converter

How the Mountain Time Zone Works

Six rules resolve the most common MT, MST, MDT and Arizona questions.

01 · MT

MT Is the Year-Round Family

Use Mountain Time or MT when you mean the seasonal zone generally without committing to MST or MDT.

02 · MST

MST Is UTC−07:00

Mountain Standard Time is Denver's winter form and also the year-round clock used by most of Arizona.

03 · MDT

MDT Is UTC−06:00

Mountain Daylight Time is the daylight-saving form used by Denver and many other seasonal MT locations.

04 · IANA

America/Denver ≠ America/Phoenix

Denver changes seasonally; Phoenix does not. Choosing the real location zone prevents summer-time errors.

05 · Boundaries

U.S. MT Is Defined Legally

The Department of Transportation maintains official Mountain boundaries, including county and municipality carve-outs in split states.

06 · 2026 Canada

Alberta Is No Longer a Simple Seasonal MT Example

Alberta adopted permanent UTC−06:00 Alberta Time in 2026, while U.S. Denver continues the MST↔MDT cycle.

Mountain Time IANA Zones — Why America/Denver Is Only a Reference

“Mountain Time” is a regional label, not one universal IANA zone. America/Denver is the best-known representative for seasonal U.S. MT, but software should store the actual location zone whenever possible. America/Phoenix, for example, intentionally behaves differently.

MST · UTC−07:00 abbreviation reference MDT · UTC−06:00 abbreviation reference MT and global abbreviations CDT · adjacent Central daylight reference Date-aware location conversion

Useful IANA Examples Inside Mountain-Time Geography

America/DenverRepresentative seasonal U.S. Mountain Time zone.
America/PhoenixMost of Arizona · MST / UTC−07:00 year-round.
America/BoiseSouthern Idaho Mountain Time history and current seasonal rules.
America/North_Dakota/BeulahNorth Dakota location-specific Mountain Time history.
America/EdmontonAlberta history plus the province's 2026 move to permanent UTC−06:00.
America/Dawson_CreekNortheastern British Columbia fixed UTC−07:00 history.

Best practice: store the location's IANA zone rather than “MT,” “MST,” “MDT” or a fixed UTC offset when historical or future rule changes matter.

Visual Geography

See the Mountain Time Zone on a Map

Use the Mountain Time Zone Map for boundary-specific intent. It shows the Central–Mountain and Mountain–Pacific boundaries, split states, West Wendover's Nevada carve-out and Arizona's distinctive DST pattern.

Open Mountain Time Zone Map U.S. Time Zone Map
MT · MST UTC−07 ↔ MDT UTC−06

Looking for the Current Time in a Mountain Time City?

Mountain Time is a zone-family reference. If your main question is the current local time in Denver, Phoenix, Salt Lake City, Boise or another location, use the geographic world clock so the correct IANA zone and DST behavior are applied.

Geographic DiscoveryWorld Clock Seasonal MTCurrent Time in Denver Fixed MSTCurrent Time in Phoenix Mountain U.S.Current Time in Salt Lake City

Sources & Methodology

U.S. Mountain Time abbreviations, offsets and 2026 daylight-saving rules are based on NIST. U.S. Mountain-zone boundaries are based on 49 CFR Part 71. Arizona's DST exception is based on NIST's current rules. Alberta's 2026 permanent UTC−06:00 change is based on the Government of Alberta. IANA location examples are used for date-aware implementation.

NIST — U.S. Time Zones, MT / MST / MDT NIST — U.S. DST Rules & Arizona Exception 49 CFR § 71.8 — Mountain Zone 49 CFR § 71.7 — Central–Mountain Boundary 49 CFR § 71.9 — Mountain–Pacific Boundary Government of Alberta — Permanent Alberta Time, UTC−06:00 IANA Time Zone Database — Location-Based Rules

Last reviewed: August 21, 2026. Representative U.S. Mountain Time is currently MDT / UTC−06:00 and returns to MST / UTC−07:00 on November 1, 2026. Most of Arizona remains MST / UTC−07:00 year-round.

Mountain Time Zone FAQ

What is the Mountain Time Zone?

Mountain Time (MT) is a North American time-zone family. Most seasonal U.S. MT locations use MST at UTC−07:00 in standard time and MDT at UTC−06:00 during daylight time.

What is Mountain Time right now, MST or MDT?

On August 21, 2026, representative U.S. Mountain Time locations such as Denver are observing MDT at UTC−06:00. They return to MST on November 1, 2026.

What is the UTC offset for Mountain Time?

MT is UTC−07:00 during MST and UTC−06:00 during MDT.

When does Mountain Time change clocks in 2026?

Seasonal U.S. MT locations moved forward on March 8, 2026 and move back on November 1, 2026, both at 2:00 AM local time.

Is MT the same as MST?

No. MT is the year-round family. MST specifically means UTC−07:00 standard time; MDT means UTC−06:00 daylight time.

What IANA time zone should I use for Mountain Time?

America/Denver is the standard representative for many seasonal U.S. MT use cases, but there is no single IANA identifier for every Mountain Time location. Arizona commonly uses America/Phoenix.

Which U.S. states use Mountain Time?

Mountain Time or Mountain Standard Time is used in all or part of 14 states. Arizona, Colorado, Montana, New Mexico, Utah and Wyoming are wholly in the federal Mountain zone; eight additional states contain Mountain areas.

Does Arizona observe daylight saving time?

Most of Arizona does not. It stays on MST / UTC−07:00 year-round. The Navajo Nation is the major exception and does observe DST.

Is Mountain Time always one hour behind Central Time?

Representative seasonal U.S. Mountain and Central Time locations remain one hour apart because they change clocks on the same dates. Arizona can differ seasonally.

Is Alberta still on Mountain Time?

Alberta historically followed MST↔MDT, but in 2026 it adopted permanent Alberta Time at UTC−06:00 and will no longer return to MST beginning in November 2026.