Saint Augustine, United States offers 12 beaches perfect for sunbathing, surfing, swimming, and more. Saint Augustine is known for the Castillo de San Marcos, the oldest masonry fort in the continental United States. The best time to travel to Saint Augustine is from March to May, with average air temperatures around 70-80°F and water temperatures around 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!