In January the difference is −17 hours, in July −15 hours. It changes because the two places do not switch to daylight saving time on the same dates. During the transition weeks in between it is −16 hours. When it is 12:00 PM (noon) in Sydney, it is 7:00 PM (previous day) in Chicago in January and 9:00 PM (previous day) in July.
Changes during 2026
- Sunday, 8 March 2026: −16 hours
- Sunday, 5 April 2026: −15 hours
- Sunday, 4 October 2026: −16 hours
- Sunday, 1 November 2026: −17 hours
Conversion table
| Sydney | Chicago |
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Green: between 8 AM and 8 PM in both places – ideal for calls and meetings.