January in Heerlen averages a daily high of 5.7°C with nights around 0.6°C. Expect roughly 15.5 wet days totalling 65.7mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Heerlen is May–September.
Based on MAASTRICHT, NL (15.6km), 1995–2024. 30 years of January data.