Green River, United States offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Green River, Utah, United States, is known for the John Wesley Powell River History Museum and its proximity to Goblin Valley State Park. The best time to travel to Green River, United States, is in late spring or early fall when the average air temperature is around 70°F (21°C) and the water temperature is approximately 60°F (16°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!