All-time weather records — Romeoville, IL

Record high
102.0°F
July 24, 2005
Record low
-24.0°F
January 16, 2009
Wettest day
4.90 in
July 27, 2003

Climate change signal in Romeoville

33.6%

of Romeoville's all-time daily heat records were set in the last decade (123 of 366 records since 2015).

34.4%

of all-time daily cold records were set in the last decade (126 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
35
29
2000s
138
143
2010s
113
139
2020s
80
55

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 64.9°F — Jan 7, 2008 -24.0°F — Jan 16, 2009 1.94 in — Jan 8, 2026
February 73.0°F — Feb 25, 2000 -14.1°F — Feb 11, 2014 2.15 in — Feb 28, 2017
March 84.9°F — Mar 21, 2012 -13.0°F — Mar 4, 2002 2.26 in — Mar 8, 2009
April 89.1°F — Apr 18, 2002 17.1°F — Apr 7, 2018 2.82 in — Apr 25, 2007
May 97.0°F — May 15, 2025 26.1°F — May 3, 2005 2.71 in — May 11, 2002
June 99.0°F — Jun 28, 2012 39.0°F — Jun 1, 2003 4.64 in — Jun 9, 2011
July 102.0°F — Jul 24, 2005 48.0°F — Jul 2, 2001 4.90 in — Jul 27, 2003
August 97.0°F — Aug 1, 2006 46.9°F — Aug 31, 2009 3.46 in — Aug 12, 2016
September 93.9°F — Sep 8, 2002 36.0°F — Sep 24, 2012 4.45 in — Sep 27, 2019
October 89.1°F — Oct 4, 2005 24.1°F — Oct 21, 2018 4.02 in — Oct 14, 2017
November 77.0°F — Nov 8, 2020 6.1°F — Nov 22, 2015 1.57 in — Nov 2, 2003
December 71.1°F — Dec 3, 2012 -11.9°F — Dec 18, 2016 2.17 in — Dec 28, 2015

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