Prior Lake, United States offers 1 beach perfect for sunbathing, surfing, swimming, and more. Prior Lake is known for Mystic Lake Casino Hotel and the Shakopee Mdewakanton Sioux Community. The best time to travel to Prior Lake, 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 is approximately 70°F. Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!