December in Nashua averages a daily high of 4.5°C with nights around -5.8°C. Expect roughly 10.4 wet days totalling 117.5mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Nashua is May–June.
Based on NASHUA 2 NNW, NH US (2.9km), 1995–2024. 30 years of December data.