Fort Gratiot Twp, United States offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Fort Gratiot Twp is known for the Fort Gratiot Lighthouse, the oldest operating lighthouse in Michigan, which attracts many tourists. The best time to travel to Fort Gratiot Twp, 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 in Lake Huron 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!