All-time weather records — Grafton, IL

Record high
106.0°F
July 7, 2012
Record low
-13.0°F
January 5, 1999
Wettest day
4.18 in
December 26, 2015

Climate change signal in Grafton

38.3%

of Grafton's all-time daily heat records were set in the last decade (140 of 366 records since 2015).

29.5%

of all-time daily cold records were set in the last decade (108 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 #
1990s
31
38
2000s
110
146
2010s
144
116
2020s
81
66

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 1997, the latest in 2026. Period of observation: 1997-2026.

Records by month

Month Hottest day Coldest day Wettest day
January 73.9°F — Jan 7, 2008 -13.0°F — Jan 5, 1999 1.91 in — Jan 3, 2005
February 99.0°F — Feb 13, 2021 -11.7°F — Feb 7, 2014 2.43 in — Feb 5, 2008
March 95.0°F — Mar 26, 2026 2.1°F — Mar 3, 2014 2.46 in — Mar 18, 2021
April 93.9°F — Apr 14, 2006 23.2°F — Apr 7, 2007 2.98 in — Apr 30, 2019
May 95.0°F — May 26, 2012 33.1°F — May 1, 2005 3.40 in — May 12, 2002
June 105.1°F — Jun 28, 2012 -0.8°F — Jun 5, 2009 3.22 in — Jun 27, 2010
July 106.0°F — Jul 7, 2012 51.1°F — Jul 28, 2013 3.81 in — Jul 16, 2024
August 102.9°F — Aug 12, 2007 -0.8°F — Aug 10, 2008 3.57 in — Aug 7, 2014
September 102.0°F — Sep 1, 2011 33.1°F — Sep 29, 2003 3.31 in — Sep 14, 2008
October 93.9°F — Oct 3, 2006 23.2°F — Oct 29, 2017 3.49 in — Oct 8, 2009
November 84.0°F — Nov 1, 2016 12.0°F — Nov 21, 2000 3.21 in — Nov 4, 2024
December 77.0°F — Dec 28, 2025 -5.8°F — Dec 23, 2022 4.18 in — Dec 26, 2015

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