December in Haarlem averages a daily high of 7°C with nights around 2°C. Expect roughly 17.6 wet days totalling 80.9mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Haarlem is May–September.
Based on SCHIPHOL, NL (12.7km), 1995–2024. 30 years of December data.