Old Mission, United States offers 1 beach perfect for sunbathing, surfing, swimming, and more. Old Mission, Michigan, United States, is known for its picturesque vineyards and wineries on the Old Mission Peninsula. The best time to travel to Old Mission, United States, is in late summer, around August, when the average air temperature is about 70°F (21°C) and the water temperature in nearby Grand Traverse Bay is approximately 68°F (20°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!