Boston, Massachusetts weather in December

Averages from 2021–2025 (155 days of record).

Average high: 42°F
Average low: 28°F
Rainy days: ~11 per month
Total precipitation: 4.4 in
Warmest recorded: 61°F
Coldest recorded: 6°F

Expect December days in Boston, Massachusetts to top out around 42°F and cool to about 28°F overnight, with roughly 11 days of measurable rain across the month. In recent years December has ranged from 6°F to 61°F.

Other months

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Current Boston, Massachusetts forecast → · Historical data by Open-Meteo (ERA5).