Mahtomedi, United States offers 1 beach perfect for sunbathing, surfing, swimming, and more. Mahtomedi, Minnesota, United States, is known for its proximity to White Bear Lake and the scenic beauty of the surrounding area. The best time to travel to Mahtomedi, United States, is in late spring (May to early June) when the average air temperature is around 60-70°F and the water temperature in nearby lakes is approximately 50-60°F. Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!