Illinois has a long and well-documented history of severe storms, with 3,339 confirmed tornadoes, 11,591 hailstorm events and 20,263 damaging-wind events recorded by the National Weather Service since 1950. The state ranks 6th nationally for tornado frequency, and averages 44.5 tornadoes per year over the 75-year record. Illinois combines a continental severe-weather season with lake-effect winter storms, giving it one of the most varied weather climates in the country. The interactive map below plots every significant severe-weather event in Illinois from the official NOAA Storm Events Database (1950 through September 2025).
Use the map to find your county, click any marker for the date, magnitude, and casualty details of that event, and switch between tornadoes, hail and wind using the chips. For the national view across all 50 states, see our NOAA Storm Reports interactive map. For tornado tracks specifically, see the US Tornado Tracks map; for hail size and frequency, the US Hailstorms map.
Illinois Severe Weather by the Numbers (1950–2025)
- 3,339 tornadoes recorded between 1950 and 2025
- 712 violent tornadoes rated F2/EF2 or stronger
- 3 confirmed F5/EF5 tornadoes on record — the maximum rating on the Fujita and Enhanced Fujita scales
- 235 direct tornado deaths and 4,610 direct injuries
- 11,591 hailstorm events recorded by the NWS
- 20,263 damaging-wind events on record
- 44.5 tornadoes per year on average across the 75-year record
- May is the peak severe-weather month, accounting for roughly 21% of Illinois tornadoes
- 1,039 total direct deaths from all severe-weather event types tracked by the NWS
When Illinois Severe Weather Happens
Illinois tornado activity is heavily concentrated in spring. March, April, May and June account for 67% of all Illinois tornadoes, with May alone responsible for roughly 21%.
- May: 701 tornadoes (21%) — peak month
- April: 654 tornadoes (19.6%)
- June: 621 tornadoes (18.6%)
- July: 307 tornadoes (9.2%)
- March: 264 tornadoes (7.9%)
- August: 237 tornadoes (7.1%)
Top 10 Illinois Counties by Tornado Frequency
Tornado activity in Illinois is geographically broad, but a handful of counties have logged many times the state average. The combination of population density (more spotters and damage reports), county land area and local climatology drives the rankings below.
| County | Tornadoes since 1950 |
|---|---|
| McLean | 119 |
| Will | 95 |
| Sangamon | 89 |
| Cook | 84 |
| Champaign | 78 |
| Macon | 76 |
| Logan | 70 |
| Tazewell | 68 |
| La Salle | 63 |
| Henry | 62 |
The Deadliest Tornadoes in Illinois History
Illinois has lost 235 lives to tornadoes since the National Weather Service began systematic tornado record-keeping in 1950. The single deadliest event killed 33 people in Cook County in 1967, rated F4 on the Fujita scale.
| Date | Location | Rating | Direct deaths | Direct injuries |
|---|---|---|---|---|
| April 21, 1967 | Cook County | F4 | 33 | 500 |
| August 28, 1990 | Will County | F5 | 29 | 350 |
| April 21, 1967 | Boone County | F4 | 24 | 410 |
| December 18, 1957 | Jackson County | F4 | 11 | 180 |
| May 29, 1982 | Williamson County | F4 | 10 | 181 |
| April 20, 2004 | La Salle County (near Peru) | F3 | 8 | 7 |
| February 29, 2012 | Saline County (near Carriers Mills) | EF4 | 8 | 95 |
| February 25, 1956 | St. Clair County | F4 | 6 | 20 |
| April 11, 1965 | McHenry County | F4 | 6 | 75 |
| August 21, 1977 | Shelby County | F3 | 6 | 56 |
Illinois Tornado Strength Distribution
Most Illinois tornadoes are weak: roughly 78% are rated F0/EF0 or F1/EF1. Violent tornadoes (F2+/EF2+) account for around 22.4% of rated tornadoes in the state. Illinois is one of the few states with a confirmed F5 or EF5 tornado on record.
- F0/EF0 (weak): 1,381 tornadoes — 43.4% of rated events
- F1/EF1: 1,088 tornadoes — 34.2% of rated events
- F2/EF2 (strong): 505 tornadoes — 15.9% of rated events
- F3/EF3: 156 tornadoes — 4.9% of rated events
- F4/EF4 (violent): 48 tornadoes — 1.5% of rated events
- F5/EF5 (incredible): 3 tornadoes — 0.1% of rated events
Record-Setting Severe Weather in Illinois
Largest hailstone: 6.00 inches in diameter, observed in Kankakee County on April 23, 1961. The three largest hailstones on record in Illinois measured 6.00″, 4.75″, 4.50″.
Highest measured wind gust: 93 knots (107 mph) recorded in Rock Island County near (Mli) Quad City Arpt on March 12, 2006. Most damaging-wind events in Illinois are estimated rather than measured because anemometers are sparse across the rural areas where supercells most often produce destructive thunderstorm winds.
How Illinois Compares Nationally
Illinois ranks 6th nationally for tornado frequency since 1950, placing it in the upper third of states by severe-weather activity.
- Tornadoes (top 5): Texas (9,908), Kansas (4,890), Oklahoma (4,856), Florida (3,779), Iowa (3,417).
- Illinois tornado total: 3,339 — ranked 6th nationally.
- Illinois hail total: 11,591 hail events on record since 1950.
- Illinois wind total: 20,263 damaging-wind events on record since 1950.
Frequently Asked Questions
How many tornadoes does Illinois have on average per year?
Illinois averages 44.5 tornadoes per year over the 1950–2025 period. Counts vary widely year to year, but the long-term mean over 75 years of NWS records is a reliable benchmark for typical activity.
What was the deadliest tornado in Illinois history?
The April 21, 1967 tornado, rated F4 on the Fujita scale, killed 33 people and injured 500 in Cook County. It remains the single deadliest tornado in the Illinois modern record.
Where in Illinois are tornadoes most common?
The single county with the most tornadoes on record is McLean County with 119 events. The three most active counties overall are McLean, Will, Sangamon.
How does Illinois compare to its neighbors?
Illinois shares a severe-weather climate with Wisconsin, Indiana, Kentucky, Missouri, Iowa. Severe storms regularly cross state lines, so the same supercells, hail cores and wind events often appear in Illinois’s neighbors’ records on the same date.
How recent is the data on this map?
The map and statistics on this page are pulled from NOAA’s official Storm Events Database, which currently runs from January 1950 through September 2025. New records typically appear in the database within 30–90 days of the event date, once damage surveys and ratings are complete.
Compare Illinois to Neighboring States
Severe weather doesn’t stop at state lines. The same supercell systems that produce Illinois tornadoes regularly cross into neighboring states. Compare Illinois’s storm history to its land neighbors:
- Wisconsin severe storm history — ranked 18th nationally, Great Lakes severe-weather and lake-effect winters
- Indiana severe storm history — ranked 16th nationally, Great Lakes severe-weather and lake-effect winters
- Kentucky severe storm history — ranked 23rd nationally, Dixie Alley state with frequent overnight tornadoes
- Missouri severe storm history — ranked 10th nationally, Dixie Alley state with frequent overnight tornadoes
- Iowa severe storm history — ranked 5th nationally, core Tornado Alley state
Explore the national NOAA Storm Reports map · US Tornado Tracks map · US Hailstorms map
