Mossyrock, United States offers 2 beaches perfect for sunbathing, surfing, swimming, and more. Mossyrock, Washington, United States, is known for the DeGoede Bulb Farm and Gardens and its proximity to Mount Rainier National Park. The best time to travel to Mossyrock, 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 nearby lakes 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!