National Weather Service United States Department of Commerce

 

This page presents a 75-year climatology of severe weather reports in the NWS Chicago forecast area which covers portion of northern Illinois and northwestern Indiana. The information herein can provide additional detail to the frequency and magnitude of local severe weather as well as rankings of the most significant events by year, number of reports, and days with at least one report. All statistics were derived by collecting and analyzing certified storm reports in NOAA's StormData publication for all counties currently being served by NWS Chicago. Edits were made to a small number of reports owing to known data quality problems within StormData (i.e., Edwards et al. 2018) and to thread together tornado reports (which were initially partitioned by county). 


Throughout this and linked pages, severe weather may be referred to "significant or "non-significant," as defined below: 

  Tornado (EF Scale) Damaging Wind Gust (More info) Hail Diameter
All Report Any Rating Any Speed >= 58 mph Any Size >=1"
Significant Report F/EF2, F/EF3, F/EF4, F/EF5 >= 75 mph >= 2"
Non-Significant Report F/EFU, F/EF0, F/EF/1 < 75 mph

< 2"

 

Page last updated: May 18, 2025

Period of record: 1950 - 2024

Find any errors or have questions? Email nws.chicago@noaa.gov

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Please acknowledge the NWS as the source of any news information accessed from this site.


Additional recaps can be found on the NWS Chicago Past Events Page
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