Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Denver to Seychelles as you normally would.
Due to multiple factors, expect to potentially pay more when booking in August. For low rates, May can be a great choice for travel to Seychelles. Flights to Seychelles from Denver in May are about $1,586 on average during May, but can be found for as low as $1,387.