Colonial Beach, United States offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Colonial Beach is known for its picturesque Potomac River beaches and the historic Colonial Beach Boardwalk. The best time to travel to Colonial Beach, United States, is from late spring to early fall, with average air temperatures ranging from 70°F to 85°F and water temperatures around 70°F to 80°F. Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!