Harrison, United States offers 4 beaches perfect for sunbathing, surfing, swimming, and more. Harrison, Idaho, United States, is known for the Trail of the Coeur d'Alenes, a renowned biking and hiking trail. The best time to travel to Harrison, United States, is in late spring (May to June) when the average air temperature is around 70°F (21°C) and 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!