All-time weather records — Waterloo, IA

Record high
105.1°F
July 31, 1988
Record low
-34.1°F
January 16, 2009
Wettest day
5.49 in
July 2, 1999

Climate change signal in Waterloo

23.2%

of Waterloo's all-time daily heat records were set in the last decade (85 of 366 records since 2015).

7.1%

of all-time daily cold records were set in the last decade (26 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 #
1950s
43
49
1960s
38
80
1970s
22
87
1980s
59
54
1990s
40
27
2000s
45
34
2010s
57
25
2020s
62
10

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 1950, the latest in 2026. Period of observation: 1950-2026.

Records by month

Month Hottest day Coldest day Wettest day
January 64.9°F — Jan 26, 2002 -34.1°F — Jan 16, 2009 2.01 in — Jan 22, 2018
February 78.1°F — Feb 26, 2024 -31.0°F — Feb 2, 1996 1.32 in — Feb 22, 1981
March 87.1°F — Mar 21, 2026 -34.1°F — Mar 1, 1962 1.95 in — Mar 30, 1998
April 100.0°F — Apr 22, 1980 -4.0°F — Apr 6, 1982 3.05 in — Apr 25, 2008
May 97.0°F — May 27, 2018 21.9°F — May 3, 2005 3.41 in — May 29, 1980
June 102.9°F — Jun 21, 1988 37.9°F — Jun 1, 1964 4.35 in — Jun 15, 1980
July 105.1°F — Jul 31, 1988 42.1°F — Jul 7, 1984 5.49 in — Jul 2, 1999
August 105.1°F — Aug 17, 1988 33.1°F — Aug 20, 1950 4.92 in — Aug 20, 1966
September 100.0°F — Sep 3, 2023 21.9°F — Sep 29, 1967 3.23 in — Sep 1, 2018
October 95.0°F — Oct 3, 1997 10.9°F — Oct 30, 1988 2.94 in — Oct 22, 2020
November 80.1°F — Nov 8, 1999 -17.0°F — Nov 26, 1977 2.40 in — Nov 4, 1959
December 73.9°F — Dec 15, 2021 -29.0°F — Dec 25, 2000 3.32 in — Dec 13, 2015

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