Frenchman Bay, Canada offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Frenchman Bay, Ontario, Canada, is known for the scenic Frenchman's Bay Marina and the nearby Petticoat Creek Conservation Area. The best time to travel to Frenchman Bay, Canada, is during the summer months of June to August, when the average air temperature is around 20°C (68°F) and the water temperature is approximately 15°C (59°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!