Offset
The time difference between Atlantic Time and Iran Standard Time is 6.5 hours.
Atlantic Time (ADT) is behind Iran Standard Time (IRST).
ADT: UTC-3
IRST: UTC+3:30
Atlantic Time is currently observing daylight saving time; Iran Standard Time is not.
When to schedule
Business-hours overlap: 9 AM–11 AM in Atlantic Time (3 PM–5 PM in Iran Standard Time).
Both teams are in working hours during this window on weekdays.
Suggested time: 10:00 AM Atlantic Time (4:30 PM Iran Standard Time).
This window may shift by an hour during daylight saving time.
Public holidays in 2026
National public holidays can affect availability — a counterpart is likely off work on their own holidays, so it's worth planning meetings and deadlines around them.
Canada
- New Year's DayThu, Jan 1
- Good FridayFri, Apr 3
- Victoria DayMon, May 18
- Canada DayWed, Jul 1
- Labour DayMon, Sep 7
- National Day for Truth and ReconciliationWed, Sep 30
- ThanksgivingMon, Oct 12
- Christmas DayFri, Dec 25
About these zones
Atlantic Time is also known as AST, or ADT. To call Canada, dial +1.
Iran Standard Time is also known as IRST. To call Iran, dial +98.
Iran Standard Time is approximately 5,550 miles northeast of Atlantic Time.
Quick reference
Full 24-hour conversion table — tap any time to open it in the converter.
| AST-ATLANTIC | IRST | Day |
|---|---|---|
| 12:00 am | 6:30 am | Same day |
| 1:00 am | 7:30 am | Same day |
| 2:00 am | 8:30 am | Same day |
| 3:00 am | 9:30 am | Same day |
| 4:00 am | 10:30 am | Same day |
| 5:00 am | 11:30 am | Same day |
| 6:00 am | 12:30 pm | Same day |
| 7:00 am | 1:30 pm | Same day |
| 8:00 am | 2:30 pm | Same day |
| 9:00 am | 3:30 pm | Same day |
| 10:00 am | 4:30 pm | Same day |
| 11:00 am | 5:30 pm | Same day |
| 12:00 pm | 6:30 pm | Same day |
| 1:00 pm | 7:30 pm | Same day |
| 2:00 pm | 8:30 pm | Same day |
| 3:00 pm | 9:30 pm | Same day |
| 4:00 pm | 10:30 pm | Same day |
| 5:00 pm | 11:30 pm | Same day |
| 6:00 pm | 12:30 am | +1 day |
| 7:00 pm | 1:30 am | +1 day |
| 8:00 pm | 2:30 am | +1 day |
| 9:00 pm | 3:30 am | +1 day |
| 10:00 pm | 4:30 am | +1 day |
| 11:00 pm | 5:30 am | +1 day |
Daylight saving time
Atlantic Time observes daylight saving time; Iran Standard Time does not. The offset between the two zones changes when Atlantic Time transitions: on Sunday, November 1, 2026, clocks fall back from ADT to AST.
See the daylight saving time page for transition dates across every time zone.
Daylight today
- Sunrise
- 5:31 AM
- Sunset
- 8:56 PM
- Day length
- 15h 25m
- Sunrise
- 4:50 AM
- Sunset
- 7:18 PM
- Day length
- 14h 28m
Daylight overlap: 7h 16m — 5:31 AM–12:48 PM in Atlantic Time (12:01 PM–7:18 PM in Iran Standard Time). Both locations are in daylight during this window.
Cities in these zones
Cities in Atlantic Time
Browse all cities to see the current local time anywhere.
Airports in these zones
Airports in Atlantic Time
- YHZ
Airports in Iran Standard Time
- IKA
- THR
- MHD
- IFN
- PYK
- TBZ
Related conversions
Common conversions
- What is 9:00 am AST-ATLANTIC in IRST?
- 9:00 am AST-ATLANTIC is 3:30 pm IRST.
- What is 12:00 pm AST-ATLANTIC in IRST?
- 12:00 pm AST-ATLANTIC is 6:30 pm IRST.
- What is 12:30 pm AST-ATLANTIC in IRST?
- 12:30 pm AST-ATLANTIC is 7:00 pm IRST.
- What is 2:00 pm AST-ATLANTIC in IRST?
- 2:00 pm AST-ATLANTIC is 8:30 pm IRST.
- What is 5:00 pm AST-ATLANTIC in IRST?
- 5:00 pm AST-ATLANTIC is 11:30 pm IRST.
- What is 11:30 pm AST-ATLANTIC in IRST?
- 11:30 pm AST-ATLANTIC is 6:00 am IRST, the next day.