IRST to Honolulu
-13h 30mIRST
IRSTSOURCEHonolulu
HSTGreen rows indicate typical business hours (9 AM - 5 PM)
IRST and HST on the World Map
The map below highlights the IRST (Iran Standard Time) and HST (Hawaii Standard Time) timezone regions across the globe.
IRST – Iran Standard Time
UTC+03:30Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.
- •IRST is one of only a few time zones with a 30-minute offset.
- •Iran observes daylight saving time, switching to IRDT (UTC+04:30).
- •Tehran has a metropolitan population of over 16 million.
HST – Hawaii Standard Time
UTC-10:00Hawaii Standard Time (HST) is the time zone for the Hawaiian Islands, 10 hours behind UTC.
- •Hawaii does not observe daylight saving time.
- •HST is 5 hours behind EST in winter and 6 hours behind EDT in summer.
- •Hawaii is one of only two US states that don't observe DST (the other is Arizona).
About Honolulu
WikipediaHonolulu operates on Hawaii Standard Time (HST), UTC-10 with no daylight saving. Hawaii's consistent time makes it a predictable connection between Asia and mainland USA.
Pearl Harbor memorial receives over 2 million visitors annually.
IRST vs Honolulu: Offsets, DST and Best Call Times
IRST runs on Iran Standard Time (IRST) at UTC+03:30. Honolulu runs on Hawaii-Aleutian Standard Time (HST) at UTC-10:00. That puts IRST 13 hours 30 minutes behind Honolulu — a difference of -13h 30m at the current offsets.
In practice, when it is 9:00 AM in IRST it is 7:30 PM in Honolulu on the previous day. Midnight in IRST is 10:30 AM in Honolulu. Neither zone observes daylight saving time, so the offset between them stays constant all year.
IRST to Honolulu time conversion table
| IRST (IRST) | Honolulu (HST) | Day |
|---|---|---|
| 12:00 AM | 10:30 AM | previous day |
| 6:00 AM | 4:30 PM | previous day |
| 7:00 AM | 5:30 PM | previous day |
| 8:00 AM | 6:30 PM | previous day |
| 9:00 AM | 7:30 PM | previous day |
| 12:00 PM | 10:30 PM | previous day |
| 3:00 PM | 1:30 AM | same day |
| 5:00 PM | 3:30 AM | same day |
| 6:00 PM | 4:30 AM | same day |
| 9:00 PM | 7:30 AM | same day |
Why people convert IRST to Honolulu time
- Scheduling a call from IRST to Honolulu: a 10:00 AM start in IRST lands at 8:30 PM in Honolulu the previous day, so you can confirm the slot without doing the arithmetic yourself.
- Handling a -13h 30m gap: IRST and Honolulu have no overlap inside a normal 9-to-5 day, so real-time meetings need an early-morning or late-evening slot on one side. 9:00 AM in Honolulu is 7:30 PM in IRST.
- Keeping family and friends in sync: knowing that 8:00 PM in IRST is 6:30 AM in Honolulu makes it easy to avoid calling at 3 AM.
- Always state the zone abbreviation, not just the hour. "3:00 PM IRST" is unambiguous; "3 PM" across a -13h 30m gap is not.
- With a -13h 30m gap there is no shared 9-to-5 window, so alternate the early start: one week IRST takes the early slot, the next week Honolulu does.
About IRST (Iran Standard Time)
Iran Standard Time (IRST) is one of the few time zones with a 30-minute offset. Iran observes daylight saving time (IRDT, UTC+04:30) from late March to late September. Tehran, the capital, is one of the largest cities in the Middle East.
About HST (Hawaii Standard Time)
Hawaii Standard Time (HST) is used in the state of Hawaii and does not observe daylight saving time. This makes HST one of the most consistent time zones in the US. The Hawaiian Islands are among the last places on Earth to see a new calendar day.
Best time to call between IRST and Honolulu
With a -13h 30m offset there is no overlap inside a normal 9 AM – 5 PM day. Honolulu opens at 9:00 AM HST, which is 7:30 PM in IRST, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
IRST and Honolulu have no shared working hours because of the -13h 30m gap. Teams need to alternate early starts or rely on asynchronous handovers.
IRST is 13 hours 30 minutes behind Honolulu (IRST UTC+03:30 → HST UTC-10:00). There is no shared 9-to-5 window, so plan around an early or late slot. Remember to re-check around daylight-saving transitions.
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between IRST and Honolulu?
IRST (IRST, UTC+03:30) is 13 hours 30 minutes behind Honolulu (HST, UTC-10:00). The gap is currently -13h 30m.
How do I convert IRST time to Honolulu time?
Add -13h 30m to IRST local time. For example, 9:00 AM in IRST is 7:30 PM in Honolulu (previous day).
What time is it in Honolulu right now?
Honolulu uses HST at UTC-10:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -13h 30m offset from IRST.
What is the best time to call Honolulu from IRST?
There is no shared working-hours window because of the -13h 30m gap. The closest option is 1:00 PM in IRST, which is 11:30 PM in Honolulu.
Which is behind, IRST or Honolulu?
IRST is 13 hours 30 minutes behind Honolulu. When it is 12:00 PM in IRST it is 10:30 PM in Honolulu.
Do IRST and Honolulu use different time zones?
IRST uses IRST at UTC+03:30, while Honolulu (USA) uses HST at UTC-10:00. The IANA identifiers are Asia/Tehran and Pacific/Honolulu.
Does daylight saving time affect the IRST–Honolulu difference?
Neither zone observes daylight saving time, so the -13h 30m offset between IRST and Honolulu is fixed all year.
Which other cities share IRST's time zone?
IRST also covers Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
Which countries use IRST, IRST's zone?
IRST is used in Iran.
Is there a day difference between IRST and Honolulu?
Sometimes. The -13h 30m gap is large enough that 8:00 PM or later in IRST already falls on the in Honolulu.
What is the time difference between IRST and Honolulu?
Honolulu is -13h 30m from IRST.
What timezone is IRST in?
IRST operates on its local timezone.
What timezone is Honolulu in?
Honolulu operates on Hawaii Standard Time (HST), UTC-10 with no daylight saving. Hawaii's consistent time makes it a predictable connection between Asia and mainland USA.
What are the business hours in Honolulu?
Standard business hours in Honolulu are 8:00 AM - 5:00 PM HST.
Which countries use IRST (Iran Standard Time)?
IRST is used in Iran.
Does IRST observe daylight saving time?
Yes, IRST switches to IRDT during summer months.
What are some interesting facts about IRST?
IRST is one of only a few time zones with a 30-minute offset. Iran observes daylight saving time, switching to IRDT (UTC+04:30).
Which cities are in the HST timezone?
Major cities in the HST timezone include Honolulu, Hilo, Kailua, Pearl City, Kapolei.
What is the UTC offset for HST?
Hawaii Standard Time (HST) is at UTC-10:00.
What should I know about the HST timezone?
Hawaii does not observe daylight saving time. HST is 5 hours behind EST in winter and 6 hours behind EDT in summer.
When is it midnight in IRST, what time is it in Honolulu?
When it is 12:00 AM (midnight) in IRST (IRST), it is -13h 30m later in Honolulu (HST).
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