Imperial Beach, United States offers 5 beaches perfect for sunbathing, surfing, swimming, and more. Imperial Beach is known for the Tijuana River National Estuarine Research Reserve and the annual U.S. Open Sandcastle Competition. The best time to travel to Imperial Beach, United States, is from June to September, with average air temperatures around 70-75°F and water temperatures around 65-70°F. Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!