Rockcastle, United States offers 1 beach perfect for sunbathing, surfing, swimming, and more. Rockcastle, Kentucky, United States, is known for the Daniel Boone National Forest and the annual Renfro Valley Gatherin'. The best time to travel to Rockcastle, United States, is in late spring (May), when the average air temperature is around 70°F (21°C) and water temperature in nearby lakes is approximately 65°F (18°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!