Best overlap: 4:00 PM to 6:00 PM in Portland is 8:00 AM to 10:00 AM in Perth.
For a call that suits both sides, look at 4:00 PM to 6:00 PM in Portland / 8:00 AM to 10:00 AM in Perth. With overlap this short — around 2 hours — a recurring slot at 4:00 PM in Portland (8:00 AM in Perth) is worth its weight in gold. One thing to flag — this overlap crosses the date line, so Perth is on the next day relative to Portland. Finally, Portland observes daylight saving and Perth doesn't, so this window shifts by an hour for part of the year — recheck it each spring and autumn.
| 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Portland America/Los Angeles | ||||||||||||||||||||||||
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. -