Barnstable, United States offers 52 beaches perfect for sunbathing, surfing, swimming, and more. Barnstable is known for the Cape Cod Maritime Museum and the Hyannis Harbor. The best time to travel to Barnstable, United States, is from June to September, when the average air temperature is around 70-80°F and the water temperature is approximately 65-70°F. Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!