MDT
Mountain Daylight Time
GMT -6
GMT/BST
Greenwich Mean Time
GMT +0
BST automatically adjusted to GMT time zone, that is in use

Time Difference

Mountain Daylight Time is 6 hours behind Greenwich Mean Time
9:00 am09:00 in MDT is 3:00 pm15:00 in GMT

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

9:00 am09:00 Mountain Daylight Time (MDT). Offset UTC -6:00 hours
3:00 pm15:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours

9:00 am09:00 MDT / 3:00 pm15:00 GMT

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

Mountain Daylight Time

Offset: MDT is 6 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 MDT timezone is Calgary from Canada with population about 1.02 million people. Other major cities in the area are Edmonton, El Paso, Denver, Albuquerque

French: HAR - Heure Avancée des Rocheuses

Spanish: MT - Zona Pacífico

MDT Time Zone Geo Map
MDT timezone map

Daylight Saving: Mountain Daylight Time (MDT) is a daylight saving/summer timezone, however during winter some places switch clocks for one hour back and observe Mountain Standard Time (MST).

Daylight saving time clock moves forward for one hour from 2am to 3amStart: Mountain Daylight Time (MDT) started on Sunday, March 9, 2025 at 2:00 am local time and clocks were set one hour forward to Sunday, March 9, 2025, 3:00 am. Daylight saving starts annually the on second Sunday of March

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

MDT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -06 - basic short
  • -0600 - basic
  • -06:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0600 - sign character (-) followed by a four digit time providing hours (06) and minutes (00) of the offset. Indicates six 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
  • Sierra - Military abbreviation for MDT
  • S - short form of 'Sierra'
IANA/Olson: Reflects MDT 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/Denver
  • America/Edmonton
  • America/Inuvik
  • America/Shiprock
  • America/Yellowknife
  • Canada/Mountain
  • MST7MDT
  • Navajo
  • US/Mountain
Time zones with the GMT -6 offset:
  • CST - Central Standard Time
  • CT - Central Time
  • MDT - Mountain Daylight Time
  • EAST - Easter Island Standard Time
  • GALT - Galapagos Time
  • S - Sierra Time Zone

British Summer Time

Offset: BST is 1 hour ahead Greenwich Mean Time (GMT) and is used in Europe

Countries: It is used in following countries: Britain (UK), Guernsey, Isle of Man, Jersey

Principal Cities: The largest city in the BST timezone is London from United Kingdom with population about 7.557 million people. Other major cities in the area are Birmingham, Glasgow, Liverpool, Saint Helier

Greenwich Mean Time (GMT) originally referred to the mean solar time at the Royal Observatory in Greenwich, London. It is now often used to refer to Coordinated Universal Time (UTC) when this is viewed as a time zone, and in casual use for the most parts it is the same. In military GMT is known as Zulu time.Greenwich Mean Time was the same as Universal Time (UT), until the introduction of UTC in 1972 a standard astronomical concept used in many technical fields.

BST Time Zone Geo Map
BST timezone map

BST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +01 - basic short
  • +0100 - basic
  • +01:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0100 - sign character (+) followed by a four digit time providing hours (01) and minutes (00) of the offset. Indicates one hour and zero minutes time differences to the east of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Alpha - Military abbreviation for BST
  • A - short form of 'Alpha'
IANA/Olson: Reflects BST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Europe/Belfast
  • Europe/Guernsey
  • Europe/Isle_of_Man
  • Europe/Jersey
  • Europe/London
  • GB
  • GB-Eire
BST Abbreviation: Several time zones share BST abbreviation and it could refer to these time zones
  • British Summer Time - UTC +1
  • Bangladesh Standard Time - UTC +6
  • Bougainville Standard Time - UTC +11
  • Brasilia Standard Time - UTC -3
Time zones with the GMT +1 offset:
  • BST - British Summer Time
  • CET - Central European Time
  • IST - Irish Standard Time
  • WEST - Western European Summer Time
  • A - Alpha Time Zone
  • CET - Central European Time
  • MEZ - Mitteleuropäische Zeit
  • WAT - West Africa Time
  • WST - Western Sahara Summer Time
  • BMT - Biel Mean Time