Due to multiple factors, expect to potentially pay more when booking in August. For low rates, February can be a great choice for travel to Newcastle upon Tyne. Flights to Newcastle upon Tyne from Edmonton in February are about C$ 1,125 on average during February, but can be found for as low as C$ 817.
Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Edmonton to Newcastle upon Tyne as you normally would.