All-time weather records — Waltham, MA

Record high
129.9°F
August 22, 2019
Record low
-20.0°F
January 18, 1957
Wettest day
8.48 in
September 11, 1954

Climate change signal in Waltham

30.1%

of Waltham's all-time daily heat records were set in the last decade (110 of 366 records since 2015).

13.9%

of all-time daily cold records were set in the last decade (51 of 366 records since 2015).

If records were spread evenly across the station's history, you'd expect roughly 5% per decade. Decade-by-decade, here's where each record-breaking day was set:

Decade Heat records set # Cold records set #
1940s
23
12
1950s
70
79
1960s
36
124
1970s
6
4
1990s
11
5
2000s
80
69
2010s
74
52
2020s
66
21

Records are the all-time daily extremes that are still standing — each daily record can only be held by one year. The station's earliest hot record was set in 1949, the latest in 2026. Period of observation: 1949-2026.

Records by month

Month Hottest day Coldest day Wettest day
January 72.0°F — Jan 12, 2020 -20.0°F — Jan 18, 1957 2.63 in — Jan 15, 1958
February 75.0°F — Feb 21, 2018 -14.8°F — Feb 24, 2015 2.20 in — Feb 13, 2008
March 82.0°F — Mar 22, 2012 -7.1°F — Mar 19, 1967 5.20 in — Mar 14, 2010
April 93.0°F — Apr 17, 2002 6.1°F — Apr 1, 1964 3.25 in — Apr 1, 2004
May 96.1°F — May 22, 2022 26.1°F — May 7, 2001 2.86 in — May 13, 2006
June 99.0°F — Jun 26, 1952 36.0°F — Jun 8, 2002 2.45 in — Jun 6, 2000
July 102.0°F — Jul 6, 2010 42.1°F — Jul 7, 1965 3.01 in — Jul 12, 2017
August 129.9°F — Aug 22, 2019 33.1°F — Aug 31, 1965 6.94 in — Aug 19, 1955
September 100.9°F — Sep 2, 1953 28.0°F — Sep 25, 1950 8.48 in — Sep 11, 1954
October 88.0°F — Oct 7, 1963 14.2°F — Oct 31, 2020 5.80 in — Oct 6, 1962
November 84.0°F — Nov 2, 1950 7.0°F — Nov 17, 1967 3.12 in — Nov 14, 2009
December 86.0°F — Dec 9, 2009 -15.0°F — Dec 31, 1963 2.94 in — Dec 18, 2023

Click a month to see every daily record for that month in Waltham.