Ottawa is 7 hours behind Cairo
Best overlap: 3:00 PM to 6:00 PM in Cairo is 8:00 AM to 11:00 AM in Ottawa.
Cairo and Ottawa overlap from 3:00 PM to 6:00 PM (Cairo) to the equivalent 8:00 AM to 11:00 AM in Ottawa — that's your meeting window. Roughly 3 hours of shared hours means scheduling takes a little care — 3:00 PM in Cairo / 8:00 AM in Ottawa is a safe default.