Fair Haven, United States offers 2 beaches perfect for sunbathing, surfing, swimming, and more. Fair Haven is known for its historic Fair Haven Green and the nearby Slate Valley Museum. The best time to travel to Fair Haven, 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 65-75°F. Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!