MST
Mountain Standard Time
GMT -7
12am
3am
6am
9am
12pm
3pm
6pm
9pm
AST/ADT
Atlantic Standard Time
GMT -4
12am
3am
6am
9am
12pm
3pm
6pm
9pm
ADT is not used on this date
This converter uses AST (GMT -4), the offset Moncton uses on this date. Open the AST converter.

Compare MST time with ADT time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.

Time Difference

Mountain Standard Time is 3 hours behind Atlantic Standard Time
5:00 am05:00 in MST is 8:00 am08:00 in AST

MST to AST call time
Best time for a conference call or a meeting is between 9am-2pm in MST which corresponds to 12pm-5pm in AST

5:00 am05:00 Mountain Standard Time (MST). Offset UTC -7:00 hours
8:00 am08:00 Atlantic Standard Time (AST). Offset UTC -4:00 hours

5:00 am05:00 MST / 8:00 am08:00 AST

MSTAST
12am (midnight)3am
1am4am
2am5am
3am6am
4am7am
5am8am
6am9am
7am10am
8am11am
9am12pm (noon)
10am1pm
11am2pm
12pm (noon)3pm
1pm4pm
2pm5pm
3pm6pm
4pm7pm
5pm8pm
6pm9pm
7pm10pm
8pm11pm
9pm12am (midnight)
10pm1am
11pm2am
00:0003:00
01:0004:00
02:0005:00
03:0006:00
04:0007:00
05:0008:00
06:0009:00
07:0010:00
08:0011:00
09:0012:00
10:0013:00
11:0014:00
12:0015:00
13:0016:00
14:0017:00
15:0018:00
16:0019:00
17:0020:00
18:0021:00
19:0022:00
20:0023:00
21:0000:00
22:0001:00
23:0002:00

Mountain Standard Time

Offset: MST is 7 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries using this time zone: Canada, Mexico, United States

Principal Cities: The largest city in the MST time zone is Phoenix in the United States, with about 1.446 million people. Other major cities in this time zone include Calgary, Edmonton, El Paso, Denver.

French: HNR - Heure Normale des Rocheuses

Spanish: MT - Zona Pacífico

MST Time Zone Geo Map
MST timezone map

Daylight Saving: This is a standard time zone. During summer, some places set clocks forward one hour for daylight saving time and observe Mountain Daylight Time (MDT).

Daylight saving time clock moves back for one hour from 2am to 1amStart: Mountain Standard Time (MST) started on Sunday, November 2, 2025 at 2:00 am local time and clocks were set one hour back to Sunday, November 2, 2025, 1:00 am. Standard time starts annually on the first Sunday of November.

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Mountain Standard Time (MST) ends on Sunday, March 8, 2026 at 2:00 am local time and clocks are set one hour forward to Sunday, March 8, 2026, 3:00 am local daylight time instead. Standard time ends annually on the second Sunday of March.

MST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -07 - basic short
  • -0700 - basic
  • -07:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0700 - sign character (-) followed by a four digit time providing hours (07) and minutes (00) of the offset. Indicates an offset of seven hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Tango - Military abbreviation for MST
  • T - short form of 'Tango'
IANA/Olson: Reflects MST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Boise
  • America/Cambridge_Bay
  • America/Ciudad_Juarez
  • America/Creston
  • America/Dawson
  • America/Dawson_Creek
  • America/Denver
  • America/Edmonton
  • America/Fort_Nelson
  • America/Hermosillo
  • America/Inuvik
  • America/Mazatlan
  • America/Phoenix
  • America/Shiprock
  • America/Whitehorse
  • America/Yellowknife
  • Canada/Mountain
  • Canada/Yukon
  • MST
  • MST7MDT
  • Mexico/BajaSur
  • Navajo
  • US/Arizona
  • US/Mountain
Time zones with the GMT -7 offset:
  • MST - Mountain Standard Time
  • PDT - Pacific Daylight Time
  • YST - Yukon Standard Time
  • T - Tango Time Zone

Atlantic Daylight Time

Offset: ADT is 3 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries using this time zone: Bermuda, Canada, Greenland

Principal Cities: The largest city in the ADT time zone is Halifax in Canada, with about 359,111 people. Other major cities in this time zone include Sydney, Dartmouth, Saint John, Moncton.

French: HAA - Heure Avancée de l'Atlantique

ADT Time Zone Geo Map
ADT timezone map

Daylight Saving: Atlantic Daylight Time (ADT) is a daylight saving/summer time zone, but some places set clocks back one hour during winter and observe Atlantic Standard Time (AST).

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Atlantic Daylight Time (ADT) ended on Sunday, November 2, 2025 at 2:00 am local time and clocks were set one hour back to Sunday, November 2, 2025, 1:00 am local standard time instead. Daylight saving ends annually on the first Sunday of November

Daylight saving time clock moves back for one hour from 2am to 1amStart: Atlantic Daylight Time (ADT) starts on Sunday, March 8, 2026 at 2:00 am local time and clocks are set one hour forward to Sunday, March 8, 2026, 3:00 am. Daylight saving starts annually on the second Sunday of March

ADT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -03 - basic short
  • -0300 - basic
  • -03:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0300 - sign character (-) followed by a four digit time providing hours (03) and minutes (00) of the offset. Indicates an offset of three hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Papa - Military abbreviation for ADT
  • P - short form of 'Papa'
IANA/Olson: Reflects ADT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Glace_Bay
  • America/Goose_Bay
  • America/Halifax
  • America/Moncton
  • America/Thule
  • Atlantic/Bermuda
  • Canada/Atlantic
Time zones with the GMT -3 offset:
  • ADT - Atlantic Daylight Time
  • PMT - Pierre & Miquelon Standard Time
  • PMST - Pierre & Miquelon Standard Time
  • AMST - Amazon Summer Time
  • ART - Argentina Time
  • BRT - Brasília time
  • CLST - Chile Summer Time
  • FKST - Falkland Islands Summer Time
  • GFT - French Guiana Time
  • P - Papa Time Zone
  • PYST - Paraguay Summer Time
  • SRT - Suriname Time
  • UYT - Uruguay Time