Mendham Township, United States offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Mendham Township, New Jersey, United States, is known for the historic Ralston Cider Mill. The best time to travel to Mendham Township, United States, is in late spring (May to June) when the average air temperature is around 65-75°F, and water temperatures in nearby lakes are typically around 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!