Best overlap: 2:00 PM to 6:00 PM in Perth is 8:00 AM to 12:00 PM in Zurich.
2:00 PM to 6:00 PM in Perth is when Zurich is also working, at 8:00 AM to 12:00 PM their time. Roughly 4 hours of common time means scheduling is manageable; just avoid the very edges of the window. Just remember Zurich changes its clocks for daylight saving and Perth doesn't, so confirm the overlap whenever the seasons turn.
| Local time | 12am | 1am | 2am | 3am | 4am | 5am | 6am | 7am | 8am | 9am | 10am | 11am | 12pm | 1pm | 2pm | 3pm | 4pm | 5pm | 6pm | 7pm | 8pm | 9pm | 10pm | 11pm |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Perth Australia/Perth | ||||||||||||||||||||||||
Zurich Europe/Zurich |
The US to Australia gap runs 14 to 19 hours depending on the month, and someone is always in tomorrow. Exact overlap windows for every US coast, the double-DST trap, and a rotation rule that keeps it fair. -