December in Parsippany averages a daily high of 6.2°C with nights around -2.4°C. Expect roughly 10.7 wet days totalling 111.2mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Parsippany is May–June.
Based on BOONTON 1 SE, NJ US (4.5km), 1995–2024. 25 years of December data.