Offset
The time difference between Central Time and Iran Standard Time is 8.5 hours.
Central Time (CDT) is behind Iran Standard Time (IRST).
CDT: UTC-5
IRST: UTC+3:30
Central Time is currently observing daylight saving time; Iran Standard Time is not.
When to schedule
Standard business hours (9 AM–5 PM, Mon–Fri) in Central Time and Iran Standard Time don't overlap on the same weekday. Iran Standard Time is 9 hours ahead of Central Time.
With some flexibility, there’s a workable window outside standard hours:
- 7 AM–12 PM in Central Time (3 PM–8 PM in Iran Standard Time) — suggest 9:00 AM Central Time (5:30 PM Iran Standard Time).
This means an early start or late finish for one side, but it’s a reasonable slot for a one-off meeting.
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.
United States
- New Year's DayThu, Jan 1
- Martin Luther King, Jr. DayMon, Jan 19
- Presidents DayMon, Feb 16
- Memorial DayMon, May 25
- Juneteenth National Independence DayFri, Jun 19
- Independence DayFri, Jul 3
- Labour DayMon, Sep 7
- Columbus DayMon, Oct 12
- Veterans DayWed, Nov 11
- Thanksgiving DayThu, Nov 26
- Christmas DayFri, Dec 25
About these zones
Central Time is also known as CST, or CDT. To call United States, dial +1.
Iran Standard Time is also known as IRST. To call Iran, dial +98.
Iran Standard Time is approximately 6,500 miles northeast of Central Time.
Quick reference
Full 24-hour conversion table — tap any time to open it in the converter.
| CST | IRST | Day |
|---|---|---|
| 12:00 am | 8:30 am | Same day |
| 1:00 am | 9:30 am | Same day |
| 2:00 am | 10:30 am | Same day |
| 3:00 am | 11:30 am | Same day |
| 4:00 am | 12:30 pm | Same day |
| 5:00 am | 1:30 pm | Same day |
| 6:00 am | 2:30 pm | Same day |
| 7:00 am | 3:30 pm | Same day |
| 8:00 am | 4:30 pm | Same day |
| 9:00 am | 5:30 pm | Same day |
| 10:00 am | 6:30 pm | Same day |
| 11:00 am | 7:30 pm | Same day |
| 12:00 pm | 8:30 pm | Same day |
| 1:00 pm | 9:30 pm | Same day |
| 2:00 pm | 10:30 pm | Same day |
| 3:00 pm | 11:30 pm | Same day |
| 4:00 pm | 12:30 am | +1 day |
| 5:00 pm | 1:30 am | +1 day |
| 6:00 pm | 2:30 am | +1 day |
| 7:00 pm | 3:30 am | +1 day |
| 8:00 pm | 4:30 am | +1 day |
| 9:00 pm | 5:30 am | +1 day |
| 10:00 pm | 6:30 am | +1 day |
| 11:00 pm | 7:30 am | +1 day |
Daylight saving time
Central Time observes daylight saving time; Iran Standard Time does not. The offset between the two zones changes when Central Time transitions: on Sunday, November 1, 2026, clocks fall back from CDT to CST.
See the daylight saving time page for transition dates across every time zone.
Daylight today
- Sunrise
- 5:18 AM
- Sunset
- 8:22 PM
- Day length
- 15h 4m
- Sunrise
- 4:50 AM
- Sunset
- 7:18 PM
- Day length
- 14h 28m
Daylight overlap: 2m — 8:20 PM–8:22 PM in Central Time (4:50 AM–4:52 AM in Iran Standard Time). Both locations are in daylight during this window.
Cities in these zones
Cities in Central Time
Browse all cities to see the current local time anywhere.
Airports in these zones
Airports in Central Time
- GYY
- MDW
- ORD
- HOU
- IAH
- SAT
- DAL
- DFW
- AUS
- BNA
Airports in Iran Standard Time
- IKA
- THR
- MHD
- IFN
- PYK
- TBZ
Related conversions
Common conversions
- What is 9:00 am CST in IRST?
- 9:00 am CST is 5:30 pm IRST.
- What is 12:00 pm CST in IRST?
- 12:00 pm CST is 8:30 pm IRST.
- What is 12:30 pm CST in IRST?
- 12:30 pm CST is 9:00 pm IRST.
- What is 2:00 pm CST in IRST?
- 2:00 pm CST is 10:30 pm IRST.
- What is 5:00 pm CST in IRST?
- 5:00 pm CST is 1:30 am IRST, the next day.
- What is 11:30 pm CST in IRST?
- 11:30 pm CST is 8:00 am IRST, the next day.