Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Atlanta to Malawi as you normally would.
Due to multiple factors, expect to potentially pay more when booking in December. For low rates, February can be a great choice for travel to Malawi. Flights to Malawi from Atlanta in February are about $1,734 on average during February, but can be found for as low as $981.