July in Marl averages a daily high of 24.5°C with nights around 13.2°C. Expect roughly 15.5 wet days totalling 94.3mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Marl is May–September.
Based on BOCHUM, GM (23.2km), 1995–2024. 13 years of July data.