Waterloo, United States offers 2 beaches perfect for sunbathing, surfing, swimming, and more. Waterloo, Iowa, United States, is known for the John Deere Tractor & Engine Museum. The best time to travel to Waterloo, United States, is in late spring (May to June) when the average air temperature is around 65-75°F and 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!