Mexico City is 15.5 hours behind Adelaide
Best overlap: 8:30 AM to 9:30 AM in Adelaide is 5:00 PM to 6:00 PM in Mexico City.
The overlap falls at 8:30 AM to 9:30 AM in Adelaide, or 5:00 PM to 6:00 PM if you're in Mexico City. Just 1 hour of shared hours means there's little margin — set 8:30 AM in Adelaide (5:00 PM in Mexico City) and start promptly. The overlap spans the date line; in practical terms, Mexico City is on the previous day compared to Adelaide. Because only Adelaide changes its clocks, the overlap above isn't fixed; expect a one-hour shift when Adelaide enters or leaves daylight saving.