Longbranch, United States offers 7 beaches perfect for sunbathing, surfing, swimming, and more. Longbranch, Washington, United States, is known for the historic Longbranch Improvement Club and its proximity to the scenic Key Peninsula. The best time to travel to Longbranch, 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 60-70°F. Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!