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Flood in Cook County, Illinois
420 floods and flash floods events in the NCEI Storm Events record, 1950 to 2026. Event types counted: Flood, Flash Flood, Coastal Flood, Lakeshore Flood.
NCEI notes that Storm Data is compiled from a variety of sources including the National Weather Service, other federal, state and local agencies, the media and the public; that property and crop damage figures are estimates; and that some events are recorded by NWS forecast zone rather than by county. FEMA notes that NFIP claim records are redacted and aggregated to protect the privacy of policyholders. Storm records through 30 Jun 2026.
NCEI records 420 flood events in Cook County, Illinois, between 1950 and 2026, spread over 31 years.
June is the busiest month, with 81 of the recorded events. The last 20 years account for 376 events against 44 in the 20 years before, a change that reflects reporting practice as much as weather.
The county holds 6.5% of the 6,507 flood events recorded in Illinois; its 44.4 per 100 square miles compares with 11.7 statewide.
NCEI attributes 3 deaths in the county to floods and flash floods.
Compared with Illinois
| Measure | Cook County | Illinois | US |
|---|---|---|---|
| Flood events since 1950 | 420 | 6,507 | 183,559 |
| Per 100 square miles | 44.4 | 11.7 | 5.2 |
| Per 10,000 residents | 0.8 | 5.1 | 5.5 |
| Deaths recorded | 3 | 61 | 2,961 |
| Busiest month | June | June | June |
By year
Seasonality
10Feb
8Mar
18Apr
26May
76Jun
81Jul
60Aug
70Sep
36Oct
25Nov
6Dec
4
Recorded events
The 188 events kept for this page are the 120 most recent plus the 80 with the most damage, deaths or injuries out of 420. Magnitude is hail size, tornado rating or wind speed as recorded.
| Date | Event type | Magnitude | Property damage | Crop damage | Deaths | Injuries | Geography |
|---|---|---|---|---|---|---|---|
| 24 Jun 2026 | Flood | — | — | — | — | — | County |
| 24 Jun 2026 | Flood | — | — | — | — | — | County |
| 24 Jun 2026 | Flood | — | — | — | — | — | County |
| 24 Jun 2026 | Flood | — | — | — | — | — | County |
| 24 Jun 2026 | Flood | — | — | — | — | — | County |
| 17 Jun 2026 | Flash Flood | — | — | — | — | — | County |
| 17 Apr 2026 | Flood | — | — | — | — | — | County |
| 17 Apr 2026 | Flood | — | — | — | — | — | County |
| 14 Apr 2026 | Flash Flood | — | — | — | — | — | County |
| 14 Apr 2026 | Flash Flood | — | — | — | — | — | County |
| 15 Mar 2026 | Flash Flood | — | — | — | — | — | County |
| 15 Mar 2026 | Flash Flood | — | — | — | — | — | County |
| 6 Mar 2026 | Flash Flood | — | — | — | — | — | County |
| 8 Jan 2026 | Flash Flood | — | — | — | — | — | County |
| 8 Jan 2026 | Flood | — | — | — | — | — | County |
| 8 Jan 2026 | Flash Flood | — | — | — | — | — | County |
| 18 Aug 2025 | Flash Flood | — | $2.5M | — | — | — | County |
| 18 Aug 2025 | Flash Flood | — | $1.5M | — | — | — | County |
| 18 Aug 2025 | Flash Flood | — | $3.5M | — | — | — | County |
| 17 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 17 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 17 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 17 Aug 2025 | Flash Flood | — | $230M | — | — | — | County |
| 17 Aug 2025 | Flash Flood | — | $2.0M | — | — | — | County |
| 17 Aug 2025 | Flash Flood | — | $55M | — | — | — | County |
| 17 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 17 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 12 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 12 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 12 Aug 2025 | Flood | — | — | — | — | — | County |
| 12 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 12 Aug 2025 | Flood | — | — | — | — | — | County |
| 12 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 12 Aug 2025 | Flood | — | — | — | — | — | County |
| 12 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 12 Aug 2025 | Flash Flood | — | — | — | — | — | County |
| 11 Aug 2025 | Flood | — | — | — | — | — | County |
| 11 Aug 2025 | Flood | — | — | — | — | — | County |
| 11 Aug 2025 | Flood | — | — | — | — | — | County |
| 11 Aug 2025 | Flood | — | — | — | — | — | County |
| 11 Aug 2025 | Flood | — | — | — | — | — | County |
| 11 Aug 2025 | Flood | — | — | — | — | — | County |
| 28 Jul 2025 | Flood | — | — | — | — | — | County |
| 25 Jul 2025 | Flood | — | — | — | — | — | County |
| 25 Jul 2025 | Flash Flood | — | $200M | — | — | — | County |
| 24 Jul 2025 | Flash Flood | — | — | — | — | — | County |
| 24 Jul 2025 | Flood | — | — | — | — | — | County |
| 11 Jul 2025 | Flood | — | — | — | — | — | County |
| 11 Jul 2025 | Flood | — | — | — | — | — | County |
| 8 Jul 2025 | Flood | — | — | — | — | — | County |
| 8 Jul 2025 | Flash Flood | — | $400K | — | — | — | County |
| 6 Jul 2025 | Flood | — | — | — | — | — | County |
| 18 Jun 2025 | Flood | — | — | — | — | — | County |
| 2 Apr 2025 | Flood | — | — | — | — | — | County |
| 2 Apr 2025 | Flood | — | — | — | — | — | County |
| 2 Apr 2025 | Flood | — | — | — | — | — | County |
| 31 Jan 2025 | Flood | — | — | — | — | — | County |
| 31 Jan 2025 | Flood | — | — | — | — | — | County |
| 31 Jan 2025 | Flood | — | — | — | — | — | County |
| 31 Jan 2025 | Flood | — | — | — | — | — | County |
| 31 Jan 2025 | Flood | — | — | — | — | — | County |
| 24 Sep 2024 | Flood | — | — | — | — | — | County |
| 24 Sep 2024 | Flood | — | — | — | — | — | County |
| 23 Jul 2024 | Flood | — | — | — | — | — | County |
| 14 Jul 2024 | Flood | — | — | — | — | — | County |
| 13 Jul 2024 | Flood | — | — | — | — | — | County |
| 13 Jul 2024 | Flood | — | — | — | — | — | County |
| 13 Jul 2024 | Flood | — | — | — | — | — | County |
| 13 Jul 2024 | Flood | — | — | — | — | — | County |
| 9 Jul 2024 | Flash Flood | — | $50K | — | — | — | County |
| 22 Jun 2024 | Flash Flood | — | — | — | — | — | County |
| 22 Jun 2024 | Flash Flood | — | — | — | — | — | County |
| 6 Jun 2024 | Flood | — | — | — | — | — | County |
| 26 May 2024 | Flood | — | — | — | — | — | County |
| 13 May 2024 | Flood | — | — | — | — | — | County |
| 7 May 2024 | Flood | — | — | — | — | — | County |
| 7 May 2024 | Flood | — | — | — | — | — | County |
| 7 May 2024 | Flash Flood | — | — | — | — | — | County |
| 2 May 2024 | Flood | — | — | — | — | — | County |
| 14 Mar 2024 | Flood | — | — | — | — | — | County |
| 14 Mar 2024 | Flood | — | — | — | — | — | County |
| 14 Mar 2024 | Flood | — | — | — | — | — | County |
| 27 Feb 2024 | Flood | — | — | — | — | — | County |
| 26 Sep 2023 | Flood | — | — | — | — | — | County |
| 26 Sep 2023 | Flood | — | — | — | — | — | County |
| 26 Sep 2023 | Flood | — | — | — | — | — | County |
| 17 Sep 2023 | Flash Flood | — | $50M | — | — | — | County |
| 17 Sep 2023 | Flood | — | — | — | — | — | County |
| 17 Sep 2023 | Flash Flood | — | — | — | — | — | County |
| 6 Sep 2023 | Flash Flood | — | — | — | — | — | County |
| 14 Aug 2023 | Flash Flood | — | — | — | — | — | County |
| 11 Jul 2023 | Flood | — | — | — | — | — | County |
| 5 Jul 2023 | Flash Flood | — | — | — | — | — | County |
| 5 Jul 2023 | Flash Flood | — | — | — | — | — | County |
| 5 Jul 2023 | Flash Flood | — | — | — | — | — | County |
| 5 Jul 2023 | Flash Flood | — | — | — | — | — | County |
| 2 Jul 2023 | Flash Flood | — | $500M | — | — | — | County |
| 2 Jul 2023 | Flash Flood | — | — | — | — | — | County |
| 4 Apr 2023 | Flood | — | — | — | — | — | County |
| 31 Mar 2023 | Flood | — | — | — | — | — | County |
| 31 Mar 2023 | Flood | — | — | — | — | — | County |
| 31 Mar 2023 | Flood | — | — | — | — | — | County |
| 31 Mar 2023 | Flood | — | — | — | — | — | County |
| 31 Mar 2023 | Flood | — | — | — | — | — | County |
| 11 Sep 2022 | Flash Flood | — | — | — | — | — | County |
| 11 Sep 2022 | Flood | — | — | — | — | — | County |
| 11 Sep 2022 | Flash Flood | — | $3.1M | — | — | — | County |
| 7 Aug 2022 | Flash Flood | — | — | — | — | — | County |
| 7 Aug 2022 | Flash Flood | — | — | — | — | — | County |
| 23 Jul 2022 | Flood | — | — | — | — | — | County |
| 13 Jun 2022 | Flood | — | — | — | — | — | County |
| 3 May 2022 | Flood | — | — | — | — | — | County |
| 3 May 2022 | Flood | — | — | — | — | — | County |
| 30 Apr 2022 | Flood | — | — | — | — | — | County |
| 24 Oct 2021 | Flood | — | — | — | — | — | County |
| 11 Oct 2021 | Flood | — | — | — | — | — | County |
| 24 Aug 2021 | Flood | — | — | — | — | — | County |
| 24 Aug 2021 | Flood | — | — | — | — | — | County |
| 24 Aug 2021 | Flash Flood | — | — | — | — | — | County |
| 24 Aug 2021 | Flash Flood | — | — | — | — | — | County |
| 11 Jan 2020 | Lakeshore Flood | — | $25M | — | — | — | Forecast zone |
| 7 Aug 2018 | Flash Flood | — | $100K | — | — | — | County |
| 30 May 2018 | Flash Flood | — | $50K | — | — | — | County |
| 18 Sep 2015 | Flash Flood | — | $10K | — | — | — | County |
| 31 Oct 2014 | Lakeshore Flood | — | $300K | — | — | — | Forecast zone |
| 22 Aug 2014 | Flash Flood | — | $50M | — | — | — | County |
| 22 Aug 2014 | Flash Flood | — | $50K | — | — | — | County |
| 4 Aug 2014 | Flash Flood | — | $150K | — | — | — | County |
| 20 May 2014 | Flash Flood | — | $20K | — | — | — | County |
| 11 May 2014 | Flood | — | $100K | — | — | — | County |
| 18 Apr 2013 | Flash Flood | — | $12M | — | — | — | County |
| 18 Apr 2013 | Flash Flood | — | $6.0M | — | — | — | County |
| 23 Jul 2011 | Flash Flood | — | $20M | — | — | — | County |
| 23 Jul 2011 | Flash Flood | — | $10M | — | — | — | County |
| 9 Jun 2011 | Flash Flood | — | $1.0M | — | — | — | County |
| 3 Aug 2010 | Flash Flood | — | $500K | — | — | — | County |
| 24 Jul 2010 | Flash Flood | — | $253M | — | — | — | County |
| 27 Jun 2010 | Flash Flood | — | $1.0M | — | — | — | County |
| 23 Jun 2010 | Flash Flood | — | $500K | — | — | — | County |
| 15 Jun 2010 | Flash Flood | — | $100K | — | — | — | County |
| 13 May 2010 | Flash Flood | — | $50K | — | — | — | County |
| 19 Jun 2009 | Flash Flood | — | $500K | — | — | — | County |
| 14 Sep 2008 | Flash Flood | — | $20M | — | — | — | County |
| 13 Sep 2008 | Flash Flood | — | $35M | — | 1 | — | County |
| 13 Sep 2008 | Flood | — | — | — | 1 | — | County |
| 13 Sep 2008 | Flood | — | $5.0M | — | — | — | County |
| 13 Sep 2008 | Flash Flood | — | $1.0M | — | — | — | County |
| 17 Feb 2008 | Flood | — | $2.0M | — | — | — | County |
| 24 Aug 2007 | Flood | — | $100K | — | — | — | County |
| 26 Jun 2007 | Flash Flood | — | $1.0M | — | — | — | County |
| 2 Oct 2006 | Flash Flood | — | $250K | — | — | — | County |
| 22 Sep 2006 | Flash Flood | — | $100K | — | — | — | County |
| 13 Sep 2006 | Flash Flood | — | $250K | — | — | — | County |
| 28 Aug 2006 | Flash Flood | — | $250K | — | — | — | County |
| 10 Aug 2006 | Flash Flood | — | $50K | — | — | — | County |
| 17 Apr 2006 | Flash Flood | — | $1.0M | — | — | — | County |
| 30 May 2004 | Flash Flood | — | — | — | — | — | County |
| 30 May 2004 | Flash Flood | — | — | — | — | — | County |
| 22 May 2004 | Flash Flood | — | — | — | — | — | County |
| 21 May 2004 | Flash Flood | — | — | — | — | — | County |
| 20 May 2004 | Flash Flood | — | — | — | — | — | County |
| 13 May 2004 | Flash Flood | — | — | — | — | — | County |
| 28 Mar 2004 | Flood | — | — | — | — | — | Forecast zone |
| 4 Nov 2003 | Flash Flood | — | — | — | — | — | County |
| 3 Aug 2003 | Flash Flood | — | $1.0M | — | — | — | County |
| 27 Jul 2003 | Flash Flood | — | $1.0M | — | — | — | County |
| 22 Aug 2002 | Flash Flood | — | — | — | — | — | County |
| 22 Aug 2002 | Flood | — | — | — | — | — | Forecast zone |
| 4 Jun 2002 | Flood | — | — | — | — | — | Forecast zone |
| 24 Oct 2001 | Flood | — | — | — | — | — | County |
| 13 Oct 2001 | Flash Flood | — | — | — | — | — | County |
| 30 Aug 2001 | Flash Flood | — | — | — | — | — | County |
| 22 Aug 2001 | Flood | — | — | — | — | — | County |
| 2 Aug 2001 | Flash Flood | — | $37M | — | — | — | County |
| 21 Jul 2001 | Flash Flood | — | $500K | — | — | — | County |
| 11 Sep 2000 | Flood | — | — | — | — | — | County |
| 11 Sep 2000 | Flood | — | — | — | — | — | County |
| 27 Apr 1999 | Flood | — | — | — | — | — | County |
| 17 Oct 1998 | Flood | — | — | — | — | — | County |
| 4 Aug 1998 | Flood | — | — | — | 1 | — | County |
| 3 Aug 1998 | Flood | — | — | — | — | — | County |
| 6 May 1998 | Flash Flood | — | — | — | — | — | County |
| 16 Aug 1997 | Flash Flood | — | — | — | — | — | County |
| 20 Feb 1997 | Flood | — | — | — | — | — | Forecast zone |
| 17 Jul 1996 | Flash Flood | — | $45M | — | — | — | County |
| 17 Jun 1996 | Flash Flood | — | — | — | — | — | County |
| 28 May 1996 | Flash Flood | — | — | — | — | — | County |
| 20 May 1996 | Flash Flood | — | — | — | — | — | County |
Questions and answers
How many flood events has Cook County had?
420 events in the NCEI Storm Events record between 1950 and 2026. Reporting of floods and flash floods became far more complete after 1996, so early decades undercount.
When was the last recorded flood event in Cook County?
24 Jun 2026 (Flood). Records reach NCEI about 120 days after the month ends.
What was the most damaging flood event recorded in Cook County?
The flash flood of 2 Jul 2023, with property damage estimated by NCEI at $500M.
How does Cook County compare with Illinois for flood?
44.4 events per 100 square miles against 11.7 statewide; the county holds 420 of the state's 6,507 recorded events.
Provenance
NOAA NCEI Storm Events Database, yearly details files through 30 Jun 2026, public domain. County-recorded events plus zone-recorded events whose forecast zone is named for the county (marked "Forecast zone"). Population and area from the US Census Bureau (2021). Built 1 Oct 2026. See the methodology, the Flood hub and the county page.