The best time to go to Iserlohn is during the late spring and summer months, from May to September, when the weather is mild and pleasant.During this period, you'll find ideal conditions for exploring the town's natural surroundings, such as the Seilersee lake, superb for a boat trip or a walk along its shores. The warmer temperatures also make it comfortable to visit the Dechenhöhle, one of Germany's most beautiful show caves, located just outside the town centre.For those interested in outdoor activities, particularly hiking or cycling, these months offer the best experience. The surrounding Märkischer Kreis region is crisscrossed with well-maintained trails, and the forests are at their most inviting.