Sydney is 16 hours ahead of Mexico City. Put the other way round: Mexico City is 16 hours behind Sydney.
Mexico City is UTC-6 in summer and UTC-6 in winter; Sydney is UTC+10 and UTC+11.
A nine-to-five in Mexico City and a nine-to-five in Sydney do not overlap at all. Somebody has to move: the nearest workable slots are early morning in one city or late evening in the other, which is the kind of thing the planner is for.
Sydney changes its clocks for summer and Mexico City does not, so there is no single answer: the gap is 16 hours for the northern summer and 17 hours for the rest of the year.
| Mexico City | Sydney |
|---|---|
| 08:00 | 00:00 next day |
| 09:00 | 01:00 next day |
| 10:00 | 02:00 next day |
| 11:00 | 03:00 next day |
| 12:00 | 04:00 next day |
| 13:00 | 05:00 next day |
| 14:00 | 06:00 next day |
| 15:00 | 07:00 next day |
| 16:00 | 08:00 next day |
| 17:00 | 09:00 next day |
| 18:00 | 10:00 next day |
This page covers one pair. TimeGap takes a list: add every city you care about, drag one marker, and every row reads the same instant on its own clock. It marks the hours you would actually take a call, finds the window where the most people are reachable, flags public holidays, and puts the time you pick straight into Outlook or Google Calendar.