Pierre, United States offers 6 beaches perfect for sunbathing, surfing, swimming, and more. Pierre is known for the South Dakota State Capitol and the nearby Oahe Dam. The best time to travel to Pierre, United States, is in late spring or early fall when the average air temperature is around 60-70°F, and the Missouri River water temperature is approximately 60°F. Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!