Hawaii Standard Time
GMT -10

Time Difference

IST (Iran Standard Time) is 13 hours and 30 minutes ahead of Hawaii Standard Time
7:00 am07:00 in Tehran, Iran is 5:30 pm17:30 in HST

Tehran to HST call time
Best time for a conference call or a meeting is between 7:30pm-9:30pm in Tehran which corresponds to 6am-8am in HST

7:00 am07:00 IST (Iran Standard Time) (Tehran, Iran). Offset UTC +3:30 hours
5:30 pm17:30 Hawaii Standard Time (HST). Offset UTC -10:00 hours

7:00 am07:00 Tehran, Iran / 5:30 pm17:30 HST

Tehran, Iran HST
12am (midnight) 10:30 am
1am 11:30 am
2am 12:30 pm
3am 1:30 pm
4am 2:30 pm
5am 3:30 pm
6am 4:30 pm
7am 5:30 pm
8am 6:30 pm
9am 7:30 pm
10am 8:30 pm
11am 9:30 pm
12pm (noon) 10:30 pm
1pm 11:30 pm
2pm 12:30 am
3pm 1:30 am
4pm 2:30 am
5pm 3:30 am
6pm 4:30 am
7pm 5:30 am
8pm 6:30 am
9pm 7:30 am
10pm 8:30 am
11pm 9:30 am
0:00 10:30
1:00 11:30
2:00 12:30
3:00 13:30
4:00 14:30
5:00 15:30
6:00 16:30
7:00 17:30
8:00 18:30
9:00 19:30
10:00 20:30
11:00 21:30
12:00 22:30
13:00 23:30
14:00 0:30
15:00 1:30
16:00 2:30
17:00 3:30
18:00 4:30
19:00 5:30
20:00 6:30
21:00 7:30
22:00 8:30
23:00 9:30

Tehran Information

Time Zone

Abbreviation / Name
IST - Iran Standard Time
IRDT - Iran Daylight Time
UTC / GMT Offset
+3:30 hours during Iran Standard Time, currently in use.
+4:30 hours during Iran Daylight Time.
Daylight Saving Time Change
+1:00 hour - DST is NOT in use
Daylight Saving Time Starts
Daylight saving time clock moves forward for one hour from 12am to 1am Monday, March 22, 2021 at 12:00 am local time. DST starts annually the on last Sunday of March. Clocks are turned forward 1 hour to Monday, March 22, 2021, 1:00 am local daylight time instead. Also called Spring Forward or Summer Time.
Daylight Saving Time Ends
Daylight saving time clock moves back for one hour from 12am to 11pm Tuesday, September 21, 2021 at 12:00 am local time. DST ends annually the on third Sunday of September. Clocks are turned backward 1 hour to Tuesday, September 21, 2021, 11:00 pm local standard time instead. Also called Fall Back or switch to Winter Time.

Tehran Facts

Alternative Names
THR, Taekhran, Tahran, Techerane, Teera, Teerao, Teerã, Teerão, Tegeran, Teheran, Teherana, Teheranas, Teherano, Teherán, Teherāna, Tehran, Tehrano, Tekheran, Téhéran, de hei lan, teharan, teharana, tehelan, teheran, tehran, teirani, thran, thrn, thrwn, tihiran, tihran, Τεχεράνη, Тæхран, Тегеран, Техеран, Теҳрон, Թեհրան, טהראן, טהרן, تهران, تهرون, تِهران, تِهِرَن, تہران, طهران, ܛܗܪܐܢ, तेहरान, তেহরান, தெஹ்ரான், เตหะราน, ཏེ་ཧི་རན​།, თეირანი, ቴህራን, テヘラン, 德黑兰, 테헤란
Rial (IRR)
Geographic Coordinates
35° 41' N Latitude / 51° 25' E Longitude
International Dialing Code

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