HDT to GMT Converter

HST/HDT

Hawaii Standard Time

GMT -10

HDT automatically adjusted to HST time zone, that is in use

GMT

Greenwich Mean Time

GMT +0

Time Difference

Hawaii Standard Time is 10 hours behind of Greenwich Mean Time
12:30 pm12:30 in HST is 10:30 pm22:30 in GMT

HDT to GMT call time
Best time for a conference call or a meeting is between 8am-10am in HDT which corresponds to 5pm-7pm in GMT

12:30 pm12:30 Hawaii Standard Time (HST). Offset UTC -10:00 hours
10:30 pm22:30 Greenwich Mean Time (GMT). Offset UTC 0:00 hours

12:30 pm12:30 HST / 10:30 pm22:30 GMT

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

Hawaii Daylight Time

Offset: HDT is 9 hours behind Greenwich Mean Time (GMT) and is used in Pacific

Countries: It is used in following countries: United States

Daylight Saving: Hawaii Daylight Time (HDT) is a daylight saving/summer timezone, however during winter some places adjust time for one hour back and observe Hawaii Standard Time (HST).

End: HDT ended and clocks were set one hour back on Sunday, 01 November 2020, at 2:00 (2:00 am) local time.

Start: HDT starts and clocks are set one hour forward on Sunday, 14 March 2021, at 2:00 (2:00 am) local time.

HDT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data

-09 - basic short
-0900 - basic
-09:00 - extended

Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers

-0900 - sign character (-) followed by a four digit time providing hours (09) and minutes (00) of the offset. Indicates nine 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

Victor - Military abbreviation for HDT
V - short form of 'Victor'

IANA/Olson: Reflects HDT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems

America/Adak
America/Atka
US/Aleutian

Time zones with the GMT -9 offset:

AKST - Alaska Standard Time
AHDT - Alaska-Hawaii Daylight Time
HADT - Hawaii-Aleutian Daylight Time
YST - Yukon Standard Time
GAMT - Gambier Time
HDT - Hawaii Daylight Time
V - Victor Time Zone
-09 -

Greenwich Mean Time

Offset: GMT is 0 hours ahead Greenwich Mean Time (GMT) and is used in Europe

Countries: It is used in following countries: Burkina Faso, Côte d'Ivoire, Britain (UK), Guernsey, Ghana, Greenland, Gambia, Guinea, Guinea-Bissau, Ireland, Isle of Man, Iceland, Jersey, Liberia, Mali, Mauritania, St Helena, Sierra Leone, Senegal, Sao Tome & Principe, Togo

Principal Cities: The largest city in the GMT timezone is London from United Kingdom with population about 7.557 million people. Other major cities in the area are Abidjan, Dakar, Grand Dakar, Accra

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.

GMT Time Zone Geo Map — GMT timezone map

GMT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data

Z - is the zone designator for the zero UTC/GMT offset, also known as 'Zulu' time
+00 - basic short
+0000 - basic
+00:00 - extended

Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers

+0000 - sign character (+) followed by a four digit time providing hours (00) and minutes (00) of the offset. Indicates zero hour and zero minutes time differences of the zero meridian.

Military/NATO: Used by the U.S. military, Chinese military and others

Zulu - Military abbreviation for GMT
Z - short form of 'Zulu'

IANA/Olson: Reflects GMT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems

Africa/Abidjan
Africa/Accra
Africa/Bamako
Africa/Banjul
Africa/Bissau
Africa/Conakry
Africa/Dakar
Africa/Freetown
Africa/Lome
Africa/Monrovia
Africa/Nouakchott
Africa/Ouagadougou
Africa/Sao_Tome
Africa/Timbuktu
America/Danmarkshavn
Atlantic/Reykjavik
Atlantic/St_Helena
Eire
Etc/GMT
Etc/GMT+0
Etc/GMT-0
Etc/GMT0
Etc/Greenwich
Europe/Belfast
Europe/Dublin
Europe/Guernsey
Europe/Isle_of_Man
Europe/Jersey
Europe/London
GB
GB-Eire
GMT
GMT+0
GMT-0
GMT0
Greenwich
Iceland

GMT Abbreviation: Several time zones share GMT abbreviation and it could refer to these time zones

Greenwich Mean Time - UTC +0
GMT-03:00 - UTC -3
GMT-01:00 - UTC -1
GMT+04:00 - UTC +4
GMT - UTC +1
GMT+11:00 - UTC +11

Time zones with the GMT +0 offset:

EGST - Eastern Greenland Summer Time
GMT - Greenwich Mean Time
WET - Western European Time
AZOST - Azores Summer Time
UTC - Universal Time Coordinated
WT - Western Sahara Standard Time
Z - Zulu Time Zone