Cedar River, United States offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Cedar River, Michigan, United States, is known for the Cedar River State Harbor and its proximity to the Hiawatha National Forest. The best time to travel to Cedar River, 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 65-75°F. Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!