Rio de Janeiro is 6 hours behind Cairo
Best overlap: 2:00 PM to 6:00 PM in Cairo is 8:00 AM to 12:00 PM in Rio de Janeiro.
If you set up a recurring sync, 2:00 PM to 6:00 PM in Cairo (8:00 AM to 12:00 PM in Rio de Janeiro) is the natural home for it. Rio de Janeiro is 6 hours behind Cairo, leaving about 4 hours of daily overlap — enough for most meetings if you don't leave them too late in the day. Because Cairo and Rio de Janeiro don't both observe daylight saving, plan to re-check the overlap around March and November.