Weather on December 21
Boston, MA
55 Years of Data
Avg High
41°F
Avg Low
27°F
Warmest
2018
54°F avg
Coldest
1989
15°F avg
About This Date
December 21st in Boston, MA typically brings chilly winter weather, with average highs around 41°F and lows near 27°F. Over 55 years of records, the warmest December 21st was in 2018 (54°F average), while the coldest was 1989 (15°F) — a 39°F range across recorded history. Precipitation has occurred on 36% of recorded December 21st dates, with snow falling 15% of the time (heaviest snowfall: 10.1"). The last decade has been 2.2°F warmer on this date compared to 20-30 years ago.
The last decade has been 2.2°F warmer on this date compared to 20-30 years ago.
Planning for December 21st in Boston, MA? Bring layers as temperatures can vary throughout the day. Consider bringing rain gear or an umbrella.
Warming Trend
0.6°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 47° | 32° | 39° | — | — |
| 2024 | 29° | 17° | 23° | — | — |
| 2023 | 36° | 24° | 30° | — | — |
| 2022 | 39° | 27° | 33° | — | — |
| 2021 | 44° | 30° | 37° | — | — |
| 2020 | 37° | 27° | 32° | — | — |
| 2019 | 35° | 22° | 29° | — | — |
| 2018warmest | 65° | 43° | 54° | 1.55" | — |
| 2017 | 33° | 26° | 30° | — | — |
| 2016 | 45° | 29° | 37° | — | — |
| 2015 | 53° | 32° | 43° | — | — |
| 2014 | 36° | 30° | 33° | — | — |
| 2013 | 54° | 41° | 47° | — | — |
| 2012 | 52° | 38° | 45° | 1.65" | — |
| 2011 | 58° | 32° | 45° | 0.23" | — |
| 2010 | 41° | 27° | 34° | 0.03" | 0.1" |
| 2009 | 32° | 20° | 26° | — | — |
| 2008 | 36° | 19° | 27° | 1.3" | 3.8" |
| 2007 | 29° | 24° | 26° | — | — |
| 2006 | 52° | 39° | 45° | — | — |
| 2005 | 30° | 20° | 25° | — | — |
| 2004 | 33° | 6° | 20° | — | — |
| 2003 | 36° | 22° | 29° | — | — |
| 2002 | 46° | 35° | 41° | — | — |
| 2001 | 39° | 31° | 35° | — | — |
| 2000 | 32° | 22° | 27° | — | — |
| 1999 | 59° | 36° | 47° | 0.23" | — |
| 1998 | 49° | 39° | 44° | — | — |
| 1997 | 33° | 20° | 26° | — | — |
| 1996 | 34° | 22° | 28° | — | — |
| 1995 | 32° | 19° | 26° | 0.13" | 0.7" |
| 1994 | 57° | 34° | 45° | — | — |
| 1993 | 56° | 37° | 46° | 3.89" | — |
| 1992 | 34° | 28° | 31° | — | — |
| 1991 | 42° | 31° | 36° | 0.25" | — |
| 1990 | 55° | 36° | 45° | 0.13" | — |
| 1989coldest | 20° | 11° | 15° | — | — |
| 1988 | 58° | 41° | 49° | — | — |
| 1987 | 46° | 34° | 40° | — | — |
| 1986 | 35° | 26° | 31° | — | — |
| 1985 | 29° | 22° | 25° | 0.03" | 0.1" |
| 1984 | 39° | 28° | 34° | 1.24" | 2.1" |
| 1983 | 25° | 9° | 17° | — | — |
| 1982 | 37° | 30° | 34° | 0.03" | 0.1" |
| 1981 | 32° | 14° | 23° | — | — |
| 1980 | 25° | 11° | 18° | — | — |
| 1979 | 35° | 23° | 29° | — | — |
| 1978 | 45° | 30° | 37° | 1.35" | — |
| 1977 | 55° | 40° | 47° | 3.4" | — |
| 1976 | 46° | 14° | 30° | 0.25" | — |
| 1975 | 35° | 19° | 27° | 1.68" | 10.1" |
| 1974 | 42° | 37° | 40° | 0.03" | — |
| 1973 | 61° | 31° | 46° | 1.78" | — |
| 1972 | 29° | 19° | 24° | 0.08" | 0.2" |
| 1971 | 45° | 30° | 37° | — | — |
55 years of data from BOSTON