Observatory log
Chicago and Tan An, compared
- 01Difference now
Tan An is 12 hours ahead of Chicago.
Chicago: CDT (UTC−5) · Tan An: UTC+7 (UTC+7)
Next changeFrom 1 November 2026: Tan An is 13 hours ahead of Chicago.
- 02Through 2026–2027
- 1 January 2026 – 8 March 2026+13 h
- 8 March 2026 – 1 November 2026+12 h
- 1 November 2026 – 14 March 2027+13 h
- 14 March 2027 – 7 November 2027+12 h
- 7 November 2027 – 31 December 2027+13 h
Difference of Tan An from Chicago. It changes on the days either place changes its clocks (dates local to that place).
- 03Shared working hours
Their working days never overlap.
Counted as 09:00–17:00 local time on each place’s own working days, for the next seven days.
- 04Best time to meet
09:00–10:00 in Chicago = 21:00–22:00 in Tan An
No shared office hours: this is early or late for one side (Mon–Fri).
Also possible: Mon–Thu: 21:00–22:00 in Chicago = 09:00–10:00 in Tan An (tomorrow) · 1 h.
- 05Weekend
Chicago: Saturday and Sunday
Tan An: Saturday and Sunday
24 hours
A day in Chicago, in Tan An
| Chicago | Tan An | Working hours, evening, night or weekend in each place |
|---|---|---|
| 00:00 | 12:00 | |
| 01:00 | 13:00 | |
| 02:00 | 14:00 | |
| 03:00 | 15:00 | |
| 04:00 | 16:00 | |
| 05:00 | 17:00 | |
| 06:00 | 18:00 | |
| 07:00 | 19:00 | |
| 08:00 | 20:00 | |
| 09:00 | 21:00 | |
| 10:00 | 22:00 | |
| 11:00 | 23:00 | |
| 12:00 | 00:00Tomorrow | |
| 13:00 | 01:00Tomorrow | |
| 14:00 | 02:00Tomorrow | |
| 15:00 | 03:00Tomorrow | |
| 16:00 | 04:00Tomorrow | |
| 17:00 | 05:00Tomorrow | |
| 18:00 | 06:00Tomorrow | |
| 19:00 | 07:00Tomorrow | |
| 20:00 | 08:00Tomorrow | |
| 21:00 | 09:00Tomorrow | |
| 22:00 | 10:00Tomorrow | |
| 23:00 | 11:00Tomorrow |
Working hoursEarly or eveningNightWeekend
Plan a meeting: Chicago and Tan An
More time differences with Chicago
Questions
Asked about Chicago and Tan An
What is the time difference between Chicago and Tan An?
Tan An is 12 hours ahead of Chicago. This holds until 1 November 2026; then Tan An is 13 hours ahead of Chicago.
What is the best time for a call between Chicago and Tan An?
No shared office hours. The least awkward windows, early or late for one side: Mon–Fri: 09:00–10:00 in Chicago = 21:00–22:00 in Tan An · 1 h; Mon–Thu: 21:00–22:00 in Chicago = 09:00–10:00 in Tan An (tomorrow) · 1 h.
When does the time difference between Chicago and Tan An change?
In the next 12 months it changes on: 1 November 2026 (+13 h); 14 March 2027 (+12 h).