Offset
The time difference between Tehran and Chicago is 8.5 hours.
Tehran (IRST) is ahead of Chicago (CDT).
IRST: UTC+3:30
CDT: UTC-5
Chicago is currently observing daylight saving time; Tehran is not.
When to schedule
Standard business hours (9 AM–5 PM, Mon–Fri) in Tehran and Chicago don't overlap on the same weekday. Chicago is 8 hours behind Tehran.
With some flexibility, there’s a workable window outside standard hours:
- 4 PM–8 PM in Tehran (7 AM–11 AM in Chicago) — suggest 6:00 PM Tehran (9:30 AM Chicago).
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
Quick reference
Full 24-hour conversion table — tap any time to open it in the converter.
| Tehran | Chicago | Day |
|---|---|---|
| 12:00 am | 3:30 pm | -1 day |
| 1:00 am | 4:30 pm | -1 day |
| 2:00 am | 5:30 pm | -1 day |
| 3:00 am | 6:30 pm | -1 day |
| 4:00 am | 7:30 pm | -1 day |
| 5:00 am | 8:30 pm | -1 day |
| 6:00 am | 9:30 pm | -1 day |
| 7:00 am | 10:30 pm | -1 day |
| 8:00 am | 11:30 pm | -1 day |
| 9:00 am | 12:30 am | Same day |
| 10:00 am | 1:30 am | Same day |
| 11:00 am | 2:30 am | Same day |
| 12:00 pm | 3:30 am | Same day |
| 1:00 pm | 4:30 am | Same day |
| 2:00 pm | 5:30 am | Same day |
| 3:00 pm | 6:30 am | Same day |
| 4:00 pm | 7:30 am | Same day |
| 5:00 pm | 8:30 am | Same day |
| 6:00 pm | 9:30 am | Same day |
| 7:00 pm | 10:30 am | Same day |
| 8:00 pm | 11:30 am | Same day |
| 9:00 pm | 12:30 pm | Same day |
| 10:00 pm | 1:30 pm | Same day |
| 11:00 pm | 2:30 pm | Same day |
Daylight saving time
Chicago observes daylight saving time; Tehran does not. The offset between the two zones changes when Chicago 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
- 4:49 AM
- Sunset
- 7:19 PM
- Day length
- 14h 30m
- Sunrise
- 5:17 AM
- Sunset
- 8:24 PM
- Day length
- 15h 7m
Daylight overlap: 5m — 4:49 AM–4:54 AM in Tehran (8:19 PM–8:24 PM in Chicago). Both locations are in daylight during this window.
Cities in these zones
Other cities in Central Time
Browse all cities to see the current local time anywhere.
Airports in these zones
Airports in Iran Standard Time
- IKA
- THR
- MHD
- IFN
- PYK
- TBZ
Airports in Central Time
- GYY
- MDW
- ORD
- HOU
- IAH
- SAT
- DAL
- DFW
- AUS
- BNA
Related conversions
Common conversions
- What is 9:00 am Tehran in Chicago?
- 9:00 am Tehran is 12:30 am Chicago.
- What is 12:00 pm Tehran in Chicago?
- 12:00 pm Tehran is 3:30 am Chicago.
- What is 12:30 pm Tehran in Chicago?
- 12:30 pm Tehran is 4:00 am Chicago.
- What is 2:00 pm Tehran in Chicago?
- 2:00 pm Tehran is 5:30 am Chicago.
- What is 5:00 pm Tehran in Chicago?
- 5:00 pm Tehran is 8:30 am Chicago.
- What is 11:30 pm Tehran in Chicago?
- 11:30 pm Tehran is 3:00 pm Chicago.