Princeton, United States offers 2 beaches perfect for sunbathing, surfing, swimming, and more. Princeton, Maine, United States, is known for the nearby Moosehorn National Wildlife Refuge. The best time to travel to Princeton, United States, is in late spring (May), when the average air temperature is around 65°F (18°C) and the nearby water temperature is approximately 60°F (16°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!