Best overlap: 8:00 AM to 11:00 AM in Geneva is 3:00 PM to 6:00 PM in Perth.
Shoot for 8:00 AM to 11:00 AM in Geneva; your Perth colleagues will see that as 3:00 PM to 6:00 PM. A 3-hour overlap gives you a workable daily window; aim for earlier in it to avoid clipping the end of someone's day. Note that Geneva follows daylight saving while Perth stays put, so the times above drift by an hour seasonally.
| 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Geneva Europe/Zurich | ||||||||||||||||||||||||
Perth Australia/Perth |
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. -