Ione, United States offers 2 beaches perfect for sunbathing, surfing, swimming, and more. Ione, California, United States, is known for the Preston Castle, a historic reform school building that attracts visitors interested in its architecture and history. The best time to travel to Ione, 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 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!