Running Water, United States offers 1 beach perfect for sunbathing, surfing, swimming, and more. Running Water, South Dakota, United States, is known for its proximity to the Missouri River and the scenic views it offers. The best time to travel to Running Water, United States, is in late spring when the average air temperature is around 70°F and the 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!