HST
Hawaii Standard Time
GMT -10
AHDT
Alaska-Hawaii Daylight Time
GMT -9

Time Difference

Hawaii Standard Time is 1 hours behind Alaska-Hawaii Daylight Time
12:00 am00:00 in HST is 1:00 am01:00 in AHDT

HST to AHDT call time
Best time for a conference call or a meeting is between 8am-5pm in HST which corresponds to 9am-6pm in AHDT

12:00 am00:00 Hawaii Standard Time (HST). Offset UTC -10:00 hours
1:00 am01:00 Alaska-Hawaii Daylight Time (AHDT). Offset UTC -9:00 hours

12:00 am00:00 HST / 1:00 am01:00 AHDT

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

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

Alaska-Hawaii Daylight Time

Offset: AHDT is 9 hours behind Greenwich Mean Time (GMT) and is used in North America

AHDT 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 AHDT
  • V - short form of 'Victor'
Time zones with the GMT -9 offset:
  • AKST - Alaska Standard Time
  • AHDT - Alaska-Hawaii Daylight Time
  • HADT - Hawaii-Aleutian Daylight Time
  • GAMT - Gambier Time
  • HDT - Hawaii Daylight Time
  • V - Victor Time Zone