Hornum, Germany offers 3 beaches perfect for sunbathing, surfing, swimming, and more. Hornum, Schleswig Holstein, Germany, is known for the Hornum Lighthouse and its scenic coastal views. The best time to travel to Hornum, Germany, is from June to August, with average air temperatures around 18°C (64°F) and water temperatures around 17°C (63°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!