Live offset · Year-round DST · Shareable URL

Time difference
Tehran and Chicago

Live clocks (IRST ↔ CST), the current gap, month-by-month offset changes, and a full 24-hour map from Tehran to Chicago.

1

Live gap

See the current offset between Tehran and Chicago, with IANA-backed clocks updating every second.

2

Year-round chart

DST can shift the gap by an hour twice a year—the 2026 month table shows every change.

3

Hour-by-hour

Scroll the 24-hour table to map any civil hour in Tehran into Chicago with day-shift cues.

Time difference workspace

How Tehran and Chicago line up today.

2 cities · live offsetGap shifts yearly
City pair

Tehran Chicago

Chicago is 8.5h behind Tehran at this moment. Compare live clocks, seasonal DST shifts, and hour-by-hour conversions below.

Live offsetIANA zones · updates automatically
Tehran
Asia/Tehran
ZoneIRST
Offset nowUTC+3:30
Hour gap
−8:30

ChicagoTehran

Chicago
America/Chicago
ZoneCST / CDT
Offset nowUTC-5
About this pairUseful when planning calls or docs

Time difference between Tehran and Chicago: Chicago is currently 9.5 hours behind Tehran.

This difference is not constant: in winter Tehran is 9.5 hours ahead of Chicago, while in summer (when one or both observe DST) the gap shifts to 8.5 hours ahead of. The monthly table below shows the exact offset gap month by month. For practical scheduling, jump to the best-time-to-meet page or the 24-hour conversion table below.

Jump aheadPick the view you need next
Best time to meetMonthly offsets24-hour table
Live clocks workspace

Clocks side by side.

Updates every second
Right nowAsia/Tehran · America/Chicago
Tehran
Asia/Tehran
Live time
--:--
OffsetUTC+3:30
AbbreviationIRST
No DST
Chicago
America/Chicago
Live time
--:--
OffsetUTC-5
AbbreviationCST / CDT
Observes DST
Relationship

Chicago is 8.5h behind Tehran.

DST rules can widen or shrink this gap for a few weeks each spring and autumn—the month table below shows how many hours Chicago sits ahead of or behind Tehran through the calendar year.

Next stepsPlan overlap or convert zones
Best time to meet →IRST → CST →Overlap Finder →
Year-round

Offset changes by month

Sampled mid-month for 2026. Compares Chicago versus Tehran; a value of +3h means Chicago is three hours ahead of Tehran.

2026 calendar

Month-by-month gap

MonthDifference (Chicago vs Tehran)
January-9.5h
February-9.5h
March-8.5h
April-8.5h
May-8.5h
June-8.5h
July-8.5h
August-8.5h
September-8.5h
October-8.5h
November-9.5h
December-9.5h
Hour by hour

24-hour conversion table

Every civil hour in Tehran mapped into Chicago; day-shift cues follow active DST for both zones today.

TehranChicago

Hourly wall-clock map for today — midnight crossings show as day shifts.

Tehran with part-of-day icon
Chicago arrow and converted time
Day
  • 00:00
    15:30
    Prev day
  • 01:00
    16:30
    Prev day
  • 02:00
    17:30
    Prev day
  • 03:00
    18:30
    Prev day
  • 04:00
    19:30
    Prev day
  • 05:00
    20:30
    Prev day
  • 06:00
    21:30
    Prev day
  • 07:00
    22:30
    Prev day
  • 08:00
    23:30
    Prev day
  • 09:00
    00:30
    Same day
  • 10:00
    01:30
    Same day
  • 11:00
    02:30
    Same day
  • 12:00
    03:30
    Same day
  • 13:00
    04:30
    Same day
  • 14:00
    05:30
    Same day
  • 15:00
    06:30
    Same day
  • 16:00
    07:30
    Same day
  • 17:00
    08:30
    Same day
  • 18:00
    09:30
    Same day
  • 19:00
    10:30
    Same day
  • 20:00
    11:30
    Same day
  • 21:00
    12:30
    Same day
  • 22:00
    13:30
    Same day
  • 23:00
    14:30
    Same day
Uses your browser's IANA zone data — choose another date in the converter for historical or future days.
Keep exploring

Related pages

More time-difference routes, pairwise best times, triple-city overlaps, and conversions tied to Tehran, Chicago, or this corridor.

FAQ

Frequently asked questions

Offsets between Tehran and Chicago, DST shifts, scheduling, and how we source timezone data—plus how to share this page.

Currently, Chicago is 8.5h behind Tehran. This may change through the year if either city observes Daylight Saving Time.