Portland is 15 hours behind Hanoi
Best overlap: 8:00 AM to 9:00 AM in Hanoi is 5:00 PM to 6:00 PM in Portland.
Schedule calls for 8:00 AM to 9:00 AM in Hanoi — your colleagues in Portland will be online from 5:00 PM to 6:00 PM. With about 1 hour of common time, this pairing rewards planning — 8:00 AM in Hanoi / 5:00 PM in Portland is the slot to defend. One thing to flag — this overlap crosses the date line, so Portland is on the previous day relative to Hanoi. Keep an eye on the calendar — Portland observes daylight saving and Hanoi doesn't, which nudges this window by an hour twice a year.