Oskaloosa, United States offers 1 beach perfect for sunbathing, surfing, swimming, and more. Oskaloosa, Iowa, United States, is known for the historic Penn Central Mall and the George Daily Auditorium. The best time to travel to Oskaloosa, United States, is in late spring (May), when the average air temperature is around 65°F (18°C) and water temperature 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!