Tehran to Halifax
-6h 30mTehran
IRSTSOURCEHalifax
ADTGreen rows indicate typical business hours (9 AM - 5 PM)
IRST and ADT on the World Map
The map below highlights the IRST (Iran Standard Time) and ADT (Atlantic 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.
AST – Atlantic Standard Time
UTC-04:00Atlantic Standard Time (AST) is the time zone for the Canadian Atlantic provinces and the Caribbean, 4 hours behind UTC.
- •Puerto Rico uses AST year-round and does not observe DST.
- •AST is 1 hour ahead of EST.
- •Halifax, the capital of Nova Scotia, is the largest city in AST Canada.
About Tehran
WikipediaTehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
Iran Standard Time (IRST) is one of few timezones with a 30-minute offset (UTC+3:30).
About Halifax
WikipediaHalifax operates on Atlantic Time (AST/ADT), UTC-4. As Canada's major Atlantic port and closest city to Europe, Halifax bridges North American and European business.
Halifax harbors the second largest natural ice-free harbor in the world.
Everything You Need to Know About Tehran and Halifax Time
Tehran runs on Iran Standard Time (IRST) at UTC+03:30. Halifax runs on Atlantic Daylight Time (ADT) at UTC-03:00, also currently on daylight saving time. That puts Tehran 6 hours 30 minutes behind Halifax — a difference of -6h 30m at the current offsets.
In practice, when it is 9:00 AM in Tehran it is 2:30 AM in Halifax. Midnight in Tehran is 5:30 PM in Halifax.Halifax observes daylight saving time while Tehran does not, so the gap narrows or widens by an hour part of the year.
Tehran to Halifax time conversion table
| Tehran (IRST) | Halifax (ADT) | Day |
|---|---|---|
| 12:00 AM | 5:30 PM | previous day |
| 6:00 AM | 11:30 PM | previous day |
| 7:00 AM | 12:30 AM | same day |
| 8:00 AM | 1:30 AM | same day |
| 9:00 AM | 2:30 AM | same day |
| 12:00 PM | 5:30 AM | same day |
| 3:00 PM | 8:30 AM | same day |
| 5:00 PM | 10:30 AM | same day |
| 6:00 PM | 11:30 AM | same day |
| 9:00 PM | 2:30 PM | same day |
Why people convert Tehran to Halifax time
- Scheduling a call from Tehran to Halifax: a 10:00 AM start in Tehran lands at 3:30 AM in Halifax, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both Tehran and Halifax are inside the 9-to-5 working day between 3:30 PM and 5:00 PM IRST time (9:00 AM–10:30 AM ADT). That is roughly 1 hours 30 minutes of usable overlap.
- Keeping family and friends in sync: knowing that 8:00 PM in Tehran is 1:30 PM in Halifax 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 -6h 30m gap is not.
- Block 3:30 PM–5:00 PM IRST as the recurring meeting window if you work primarily from Tehran and need Halifax colleagues present.
- Halifax: Clocks fall back on Sun, Nov 1, 2026. Any meeting series spanning that date will shift by an hour in local time.
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 AST (Atlantic Standard Time)
Atlantic Standard Time (AST) covers Canada's Atlantic provinces (Nova Scotia, New Brunswick, Prince Edward Island, and most of Labrador), as well as several Caribbean nations. Puerto Rico and the US Virgin Islands use AST year-round without daylight saving time. The Canadian provinces switch to Atlantic Daylight Time (ADT) in summer.
Best time to call between Tehran and Halifax
Both Tehran and Halifax sit inside the 9 AM – 5 PM working day between 3:30 PM–5:00 PM IRST, which is 9:00 AM–10:30 AM ADT. That gives roughly 1 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
Tehran and Halifax overlap for only 90 minutes (3:30 PM–5:00 PM IRST), so meetings have to be booked precisely.
Tehran is 6 hours 30 minutes behind Halifax (IRST UTC+03:30 → ADT UTC-03:00). The shared working window is 3:30 PM–5:00 PM IRST. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
Tehran
Does not observe DST
Halifax
☀ Currently in DST
Standard: UTC-04:00 · DST: UTC-03:00
Clocks fall back on Sun, Nov 1, 2026
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 Tehran and Halifax?
Tehran (IRST, UTC+03:30) is 6 hours 30 minutes behind Halifax (ADT, UTC-03:00). The gap is currently -6h 30m.
How do I convert Tehran time to Halifax time?
Add -6h 30m to Tehran local time. For example, 9:00 AM in Tehran is 2:30 AM in Halifax.
What time is it in Halifax right now?
Halifax uses ADT at UTC-03:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -6h 30m offset from Tehran.
What is the best time to call Halifax from Tehran?
Call between 3:30 PM and 5:00 PM IRST — that maps to 9:00 AM–10:30 AM ADT and keeps both parties inside the working day.
Which is behind, Tehran or Halifax?
Tehran is 6 hours 30 minutes behind Halifax. When it is 12:00 PM in Tehran it is 5:30 AM in Halifax.
Do Tehran and Halifax use different time zones?
Tehran (Iran) uses IRST at UTC+03:30, while Halifax (Canada) uses ADT at UTC-03:00. The IANA identifiers are Asia/Tehran and America/Halifax.
Does daylight saving time affect the Tehran–Halifax difference?
Yes at the moment: Halifax is on daylight saving time and Tehran is not, so the -6h 30m gap shifts by an hour when exactly one of them changes clocks.
Which other cities share Tehran's time zone?
IRST also covers Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
Which countries use IRST, Tehran's zone?
IRST is used in Iran.
Is there a day difference between Tehran and Halifax?
Not normally. The -6h 30m gap only pushes the date over the previous day.
What is the time difference between Tehran and Halifax?
Halifax is -6h 30m from Tehran.
What timezone is Tehran in?
Tehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
What timezone is Halifax in?
Halifax operates on Atlantic Time (AST/ADT), UTC-4. As Canada's major Atlantic port and closest city to Europe, Halifax bridges North American and European business.
What are the business hours in Tehran?
Standard business hours in Tehran are 8:00 AM - 4:00 PM IRST.
What are the business hours in Halifax?
Standard business hours in Halifax are 9:00 AM - 5:00 PM AST.
What is the best time to schedule a call between Tehran and Halifax?
The best overlap for a call is when both cities are in business hours. Tehran works 8:00 AM - 4:00 PM IRST and Halifax works 9:00 AM - 5:00 PM AST (-6h 30m difference). Try scheduling during the overlapping window for maximum convenience.
What currencies are used in Tehran and Halifax?
Tehran uses IRR (﷼) while Halifax uses CAD (C$). Check current exchange rates when planning travel or business between these cities.
How do Tehran and Halifax compare in size?
Tehran has a population of approximately 9.4 million (metro: 16.8 million), while Halifax has approximately 440,000 (metro: 465,000).
What are the major landmarks in Tehran and Halifax?
Tehran is known for Azadi Tower, Golestan Palace, Grand Bazaar. Halifax is famous for Halifax Citadel, Peggy's Cove, Halifax Waterfront.
Do Tehran and Halifax have stock exchanges?
Yes. Tehran has the TSE (Tehran Stock Exchange) and Halifax has the N/A (Uses TSX). The -6h 30m time difference affects trading hour overlaps between these exchanges.
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 AST timezone?
Major cities in the AST timezone include Halifax, San Juan, Santo Domingo, Caracas, La Paz, Fredericton, Charlottetown.
What is the UTC offset for AST?
Atlantic Standard Time (AST) is at UTC-04:00. During daylight saving time, it shifts to ADT.
What should I know about the AST timezone?
Puerto Rico uses AST year-round and does not observe DST. AST is 1 hour ahead of EST.
When is it midnight in Tehran, what time is it in Halifax?
When it is 12:00 AM (midnight) in Tehran (IRST), it is -6h 30m later in Halifax (AST).
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