National Harbor, United States offers 1 beach perfect for sunbathing, surfing, swimming, and more. Maybole is known for Culzean Castle and Country Park in regard to tourism. The best time to visit National Harbor is in late spring (May to early June) when the average air temperature is around 70-80°F and the water temperature 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!