All-time weather records — Janesville, WI

Record high
102.9°F
July 6, 2012
Record low
-31.0°F
February 3, 1996
Wettest day
4.22 in
August 5, 2007

Climate change signal in Janesville

30.9%

of Janesville's all-time daily heat records were set in the last decade (113 of 366 records since 2015).

20.8%

of all-time daily cold records were set in the last decade (76 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 #
1980s
34
53
1990s
81
143
2000s
76
64
2010s
107
73
2020s
68
33

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 1988, the latest in 2026. Period of observation: 1987-2026.

Records by month

Month Hottest day Coldest day Wettest day
January 60.1°F — Jan 7, 2008 -29.9°F — Jan 31, 2019 1.80 in — Jan 5, 2004
February 73.9°F — Feb 28, 2024 -31.0°F — Feb 3, 1996 1.65 in — Feb 9, 2001
March 82.9°F — Mar 22, 2012 -11.9°F — Mar 1, 2015 2.67 in — Mar 25, 2009
April 89.1°F — Apr 19, 2002 15.1°F — Apr 5, 1995 3.62 in — Apr 18, 2026
May 96.1°F — May 28, 2018 27.0°F — May 4, 2005 2.80 in — May 13, 2014
June 100.9°F — Jun 20, 1988 36.0°F — Jun 1, 1993 3.36 in — Jun 4, 2025
July 102.9°F — Jul 6, 2012 45.0°F — Jul 2, 2001 4.04 in — Jul 29, 2016
August 102.0°F — Aug 1, 1988 43.0°F — Aug 16, 1992 4.22 in — Aug 5, 2007
September 96.1°F — Sep 2, 2000 28.0°F — Sep 23, 1995 2.96 in — Sep 12, 2022
October 89.1°F — Oct 4, 2025 14.0°F — Oct 29, 1988 2.80 in — Oct 24, 2001
November 75.9°F — Nov 2, 2016 -4.0°F — Nov 29, 1995 2.66 in — Nov 5, 2022
December 66.9°F — Dec 6, 2001 -25.1°F — Dec 25, 2000 1.66 in — Dec 14, 2015

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