December in Dorchester averages a daily high of 6°C with nights around -3.1°C. Expect roughly 11.6 wet days totalling 140mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Dorchester is May–June.
Based on JAMAICA PLAIN, MA US (4.1km), 1995–2024. 27 years of December data.