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 Chicago, it is 5:00 AM (next day) in Sydney in January and 3:00 AM (next 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
| Chicago | Sydney |
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Green: between 8 AM and 8 PM in both places – ideal for calls and meetings.