Portland is 9 hours behind Frankfurt
Best overlap: 5:00 PM to 6:00 PM in Frankfurt is 8:00 AM to 9:00 AM in Portland.
Schedule calls for 5:00 PM to 6:00 PM in Frankfurt — your colleagues in Portland will be online from 8:00 AM to 9:00 AM. Since Portland is 9 hours behind Frankfurt, the overlap is narrow (about 1 hour); a single, well-protected slot beats hunting for time each week.