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HADT to HST Converter

Updating current time…
HADT
Hawaii-Aleutian Daylight Time
GMT -9
12am
3am
6am
9am
12pm
3pm
6pm
9pm
HST
Hawaii Standard Time
GMT -10
12am
3am
6am
9am
12pm
3pm
6pm
9pm

Quick answers

Selected conversion

3:00 am03:00 HADT (UTC-9), Oct 4, 2026 = 2:00 am02:00 HST (UTC-10), Oct 4, 2026

HADT is 1 hour ahead of HST.

HADT and HST examples

These examples always use HADT (UTC-9) and HST (UTC-10). They stay the same when you change the date or time above. The selected conversion may differ when daylight saving time applies.

HADT is 1 hour ahead of HST.

How the time difference changes

For most of the year, HADT is 1 hour ahead of HST. At other times of the year, the HADT and HST converter rows show the same time.

For most of the year, working hours of 9:00 am to 5:00 pm in HADT correspond to 8:00 am to 4:00 pm in HST. At other times of the year, working hours of 9:00 am to 5:00 pm on the HADT converter row correspond to 9:00 am to 5:00 pm on the HST converter row.For most of the year, working hours of 09:00 to 17:00 in HADT correspond to 08:00 to 16:00 in HST. At other times of the year, working hours of 09:00 to 17:00 on the HADT converter row correspond to 09:00 to 17:00 on the HST converter row.

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

Time Difference

Hawaii-Aleutian Daylight Time is 1 hour ahead of Hawaii Standard Time.
3:00 am03:00 in HADT is 2:00 am02:00 in HST

HADT to HST call time
Best time for a conference call or a meeting is between 10am-5pm10:00-17:00 in HADT which corresponds to 9am-4pm09:00-16:00 in HST

3:00 am03:00 Hawaii-Aleutian Daylight Time (HADT). Offset UTC -9:00 hours
2:00 am02:00 Hawaii Standard Time (HST). Offset UTC -10:00 hours

3:00 am03:00 HADT / 2:00 am02:00 HST

HADTHST
12:00am11:00pm
1:00am12:00am
2:00am1:00am
3:00am2:00am
4:00am3:00am
5:00am4:00am
6:00am5:00am
7:00am6:00am
8:00am7:00am
9:00am8:00am
10:00am9:00am
11:00am10:00am
12:00pm11:00am
1:00pm12:00pm
2:00pm1:00pm
3:00pm2:00pm
4:00pm3:00pm
5:00pm4:00pm
6:00pm5:00pm
7:00pm6:00pm
8:00pm7:00pm
9:00pm8:00pm
10:00pm9:00pm
11:00pm10:00pm
00:0023:00
01:0000:00
02:0001:00
03:0002:00
04:0003:00
05:0004:00
06:0005:00
07:0006:00
08:0007:00
09:0008:00
10:0009:00
11:0010:00
12:0011:00
13:0012:00
14:0013:00
15:0014:00
16:0015:00
17:0016:00
18:0017:00
19:0018:00
20:0019:00
21:0020:00
22:0021:00
23:0022:00

Hawaii-Aleutian Daylight Time

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

Daylight Saving: Hawaii-Aleutian Daylight Time (HADT) is a daylight saving/summer time zone. During winter, some places set clocks back one hour and observe Hawaii-Aleutian Standard Time (HAST).

Daylight saving time clock moves forward for one hourStart: Hawaii-Aleutian Daylight Time (HADT) started on Sunday, March 8, 2026 at 2:00 am02:00 local time and clocks were set one hour forward to Sunday, March 8, 2026, 3:00 am03:00. Daylight saving starts annually on the second Sunday of March.

Daylight saving time clock moves back for one hourEnd: Hawaii-Aleutian Daylight Time (HADT) ends on Sunday, November 1, 2026 at 2:00 am02:00 local time and clocks are set one hour back to Sunday, November 1, 2026, 1:00 am01:00 local standard time instead. Daylight saving ends annually on the first Sunday of November.

See upcoming clock changes worldwide.

HADT 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 an offset of nine hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Victor - Military abbreviation for HADT
  • 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

Hawaii Standard Time

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

Countries using this time zone: United States

Principal Cities: The largest city in the HST time zone is Honolulu in the United States, with about 350,964 people. Other major cities in this time zone include Pearl City, Hilo, Kailua, Waipahu.

Daylight Saving: Clocks in Hawaii Standard Time (HST) do not change for daylight saving time, so HST stays the same throughout the year. Other time zones may set clocks forward in summer and back in winter; see upcoming clock changes worldwide.

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 an offset of ten hours 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
EST to ISTGMT to ESTPST to ESTEST to GMTPST to GMT