Petoskey, United States offers 7 beaches perfect for sunbathing, surfing, swimming, and more. Petoskey, Michigan, United States, is known for its Petoskey Stones and the historic Gaslight Shopping District. The best time to travel to Petoskey, United States, is during the summer months of June to August, when the average air temperature is around 70-80°F and the water temperature in Lake Michigan is approximately 60-70°F. Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!