HST
Hawaii Standard Time
GMT -10
MST
Mountain Standard Time
GMT -7

Time Difference

Hawaii Standard Time is 3 hours behind Mountain Standard Time
10:30 am10:30 in HST is 1:30 pm13:30 in MST

HST to MST call time
Best time for a conference call or a meeting is between 8am-3pm in HST which corresponds to 11am-6pm in MST

10:30 am10:30 Hawaii Standard Time (HST). Offset UTC -10:00 hours
1:30 pm13:30 Mountain Standard Time (MST). Offset UTC -7:00 hours

10:30 am10:30 HST / 1:30 pm13:30 MST

HST MST
12am (midnight) 3am
1am 4am
2am 5am
3am 6am
4am 7am
5am 8am
6am 9am
7am 10am
8am 11am
9am 12pm (noon)
10am 1pm
11am 2pm
12pm (noon) 3pm
1pm 4pm
2pm 5pm
3pm 6pm
4pm 7pm
5pm 8pm
6pm 9pm
7pm 10pm
8pm 11pm
9pm 12am (midnight)
10pm 1am
11pm 2am
0:00 3:00
1:00 4:00
2:00 5:00
3:00 6:00
4:00 7:00
5:00 8:00
6:00 9:00
7:00 10:00
8:00 11:00
9:00 12:00
10:00 13:00
11:00 14:00
12:00 15:00
13:00 16:00
14:00 17:00
15:00 18:00
16:00 19:00
17:00 20:00
18:00 21:00
19:00 22:00
20:00 23:00
21:00 0:00
22:00 1:00
23:00 2:00

Hawaii Standard Time

Offset: HST is 10 hours behind Greenwich Mean Time (GMT) and is used in Pacific

Countries: It is used in following countries: United States

Principal Cities: The largest city in the HST timezone is Honolulu from USA with population about 371,657 people. Other major cities in the area are Pearl City, Hilo, Kailua, Waipahu

Daylight Saving: Hawaii Standard Time (HST) is not adjusted for daylight saving therefore HST remains the same through out the year. This means, unlike some time zones where the clock is set forward by one hour every summer and backward by one hour during winter to adjust for daylight saving, Hawaii Standard Time remains the same

HST Time Zone Geo Map
HST timezone map

HST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -10 - basic short
  • -1000 - basic
  • -10:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -1000 - sign character (-) followed by a four digit time providing hours (10) and minutes (00) of the offset. Indicates ten hour and zero minutes time differences to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Whiskey - Military abbreviation for HST
  • W - short form of 'Whiskey'
IANA/Olson: Reflects HST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Adak
  • America/Atka
  • HST
  • Pacific/Honolulu
  • Pacific/Johnston
  • US/Aleutian
  • US/Hawaii
Time zones with the GMT -10 offset:
  • HAST - Hawaii-Aleutian Standard Time
  • CKT - Cook Island Time
  • HST - Hawaii Standard Time
  • TAHT - Tahiti Time
  • W - Whiskey Time Zone

Mountain Standard Time

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

Countries: It is used in following countries: Canada, Mexico, United States

Principal Cities: The largest city in the MST timezone is Phoenix from USA with population about 1.446 million people. Other major cities in the area are 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 timezone, however during summer some places switch clocks for one hour forward when daylight saving comes into effect 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 the on 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 starts annually the on 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 seven hour and zero minutes time differences 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
MST Abbreviation: Several time zones share MST abbreviation and it could refer to these time zones
  • Mountain Standard Time - UTC -7
  • Mauritius Standard Time - UTC +4
  • Moscow Standard Time - UTC +3
  • Magadan Standard Time - UTC +11
Time zones with the GMT -7 offset:
  • MST - Mountain Standard Time
  • PDT - Pacific Daylight Time
  • YST - Yukon Standard Time
  • T - Tango Time Zone