Weather on May 21
Boston, MA
55 Years of Data
Avg High
70°F
Avg Low
52°F
Warmest
1996
79°F avg
Coldest
1990
43°F avg
About This Date
May 21st in Boston, MA typically brings pleasant spring weather, with average highs around 70°F and lows near 52°F. Over 55 years of records, the warmest May 21st was in 1996 (79°F average), while the coldest was 1990 (43°F) — a 36°F range across recorded history. Rain or other precipitation has occurred on about 40% of May 21st dates historically, with the wettest May 21st recording 1.3" of rain. The last decade has been 3.5°F warmer on this date compared to 20-30 years ago.
The last decade has been 3.5°F warmer on this date compared to 20-30 years ago.
Planning for May 21st in Boston, MA? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 50° | 47° | 48° | — | — |
| 2024 | 84° | 53° | 69° | — | — |
| 2023 | 76° | 61° | 68° | 0.28" | — |
| 2022 | 71° | 54° | 62° | 0.05" | — |
| 2021 | 82° | 56° | 69° | — | — |
| 2020 | 77° | 45° | 61° | — | — |
| 2019 | 72° | 58° | 65° | — | — |
| 2018 | 80° | 57° | 69° | — | — |
| 2017 | 61° | 48° | 54° | — | — |
| 2016 | 76° | 53° | 64° | — | — |
| 2015 | 67° | 45° | 56° | — | — |
| 2014 | 65° | 52° | 58° | — | — |
| 2013 | 66° | 52° | 59° | 0.03" | — |
| 2012 | 59° | 54° | 56° | 0.05" | — |
| 2011 | 62° | 49° | 55° | — | — |
| 2010 | 69° | 54° | 61° | — | — |
| 2009 | 92° | 59° | 75° | — | — |
| 2008 | 71° | 50° | 61° | — | — |
| 2007 | 66° | 50° | 58° | — | — |
| 2006 | 68° | 45° | 56° | 0.28" | — |
| 2005 | 54° | 46° | 50° | 0.58" | — |
| 2004 | 77° | 54° | 65° | — | — |
| 2003 | 70° | 55° | 62° | 0.23" | — |
| 2002 | 62° | 43° | 52° | — | — |
| 2001 | 58° | 50° | 54° | — | — |
| 2000 | 53° | 49° | 51° | 0.03" | — |
| 1999 | 66° | 50° | 58° | — | — |
| 1998 | 82° | 55° | 69° | — | — |
| 1997 | 62° | 47° | 54° | 0.15" | — |
| 1996warmest | 91° | 66° | 79° | 0.23" | — |
| 1995 | 80° | 53° | 67° | — | — |
| 1994 | 73° | 44° | 59° | — | — |
| 1993 | 70° | 50° | 60° | — | — |
| 1992 | 82° | 55° | 69° | — | — |
| 1991 | 84° | 53° | 69° | — | — |
| 1990coldest | 45° | 42° | 43° | 0.53" | — |
| 1989 | 80° | 58° | 69° | 0.13" | — |
| 1988 | 59° | 49° | 54° | 0.28" | — |
| 1987 | 69° | 45° | 57° | — | — |
| 1986 | 77° | 57° | 67° | 0.61" | — |
| 1985 | 77° | 61° | 69° | 0.94" | — |
| 1984 | 70° | 54° | 62° | 0.2" | — |
| 1983 | 79° | 60° | 69° | 0.08" | — |
| 1982 | 66° | 55° | 61° | — | — |
| 1981 | 68° | 50° | 59° | — | — |
| 1980 | 54° | 46° | 50° | 0.53" | — |
| 1979 | 67° | 53° | 60° | 0.03" | — |
| 1978 | 77° | 60° | 69° | 0.15" | — |
| 1977 | 77° | 59° | 68° | — | — |
| 1976 | 58° | 48° | 53° | 1.3" | — |
| 1975 | 89° | 55° | 72° | — | — |
| 1974 | 59° | 48° | 54° | — | — |
| 1973 | 65° | 52° | 58° | 0.33" | — |
| 1972 | 75° | 50° | 63° | — | — |
| 1971 | 60° | 48° | 54° | — | — |
55 years of data from BOSTON