December in Brookline 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 Brookline is May–June.
Based on JAMAICA PLAIN, MA US (3.2km), 1995–2024. 27 years of December data.