Post Falls, United States offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Post Falls, Idaho, United States, is known for the Spokane River, Q'emiln Park, and the nearby Coeur d'Alene National Forest. The best time to travel to Post Falls, United States, is during the summer months of June to August, when the average air temperature is around 75°F (24°C) and the water temperature in nearby lakes is approximately 68°F (20°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!