Weather alerts in Illinois, 2026
3,350 weather alerts in 2026, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered any part of the state, so the counties below add up to more than the state.
Weather alerts by county
Each county as a circle sized by its count in 2026. Tap one for its archive.
- Alerts
- 3,350
- Warnings
- 2,032
- Watches
- 254
- Advisories
- 521
- Busiest month
- June739 alerts
- Busiest day
- April 27, 2026136 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
118 of 333 tornado warnings covering Illinois in 2026 had a tornado report inside them; 201 of 295 tornado reports fell inside a warning, on average 16 minutes after it went out.
Illinois, 2026
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 333 | 118 | 65% | 295 | 68% | 16 min |
| Severe thunderstorm warnings | 1,027 | 540 | 47% | 2,428 | 85% | 26 min |
| Flash flood warnings | 219 | 113 | 48% | 339 | 83% | 117 min |
Each office's whole area, 2026
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Indianapolis, IN: tornado warnings | 78 | 17 | 78% | 26 | 62% | 14 min |
| NWS Indianapolis, IN: severe thunderstorm warnings | 355 | 231 | 35% | 493 | 81% | 22 min |
| NWS Indianapolis, IN: flash flood warnings | 87 | 58 | 33% | 81 | 95% | 120 min |
| NWS Paducah, KY: tornado warnings | 92 | 27 | 71% | 53 | 85% | 17 min |
| NWS Paducah, KY: severe thunderstorm warnings | 364 | 184 | 49% | 453 | 75% | 22 min |
| NWS Paducah, KY: flash flood warnings | 91 | 43 | 53% | 89 | 88% | 108 min |
| NWS Chicago, IL: tornado warnings | 75 | 29 | 61% | 91 | 69% | 19 min |
| NWS Chicago, IL: severe thunderstorm warnings | 265 | 167 | 37% | 1,194 | 90% | 30 min |
| NWS Chicago, IL: flash flood warnings | 59 | 31 | 47% | 188 | 86% | 119 min |
| NWS Lincoln, IL: tornado warnings | 142 | 59 | 58% | 143 | 71% | 13 min |
| NWS Lincoln, IL: severe thunderstorm warnings | 380 | 180 | 53% | 886 | 83% | 22 min |
| NWS Lincoln, IL: flash flood warnings | 81 | 37 | 54% | 103 | 79% | 127 min |
| NWS Quad Cities, IA: tornado warnings | 93 | 25 | 73% | 49 | 65% | 22 min |
| NWS Quad Cities, IA: severe thunderstorm warnings | 290 | 168 | 42% | 599 | 80% | 25 min |
| NWS Quad Cities, IA: flash flood warnings | 50 | 33 | 34% | 61 | 89% | 103 min |
| NWS St. Louis, MO: tornado warnings | 80 | 18 | 78% | 57 | 61% | 20 min |
| NWS St. Louis, MO: severe thunderstorm warnings | 258 | 110 | 57% | 561 | 76% | 21 min |
| NWS St. Louis, MO: flash flood warnings | 61 | 25 | 59% | 82 | 76% | 97 min |
| NWS Milwaukee, WI: tornado warnings | 86 | 16 | 81% | 36 | 72% | 15 min |
| NWS Milwaukee, WI: severe thunderstorm warnings | 274 | 120 | 56% | 423 | 88% | 29 min |
| NWS Milwaukee, WI: flash flood warnings | 22 | 8 | 64% | 24 | 58% | 40 min |
An office's figures cover every county it serves, including across state lines.
The year is still running; reports filed late and damage surveys can still change these figures.
Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.
The alerts
3,350 alerts are too many to list on one page. Narrow it to a product above, to a month in the chart, or to a county.
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Cook County320
- Will County262
- McLean County216
- LaSalle County208
- Tazewell County206
- DuPage County199
- Rock Island County188
- Woodford County184
- Mason County183
- Vermilion County182
- Champaign County181
- Fulton County181
- Sangamon County179
- Kane County179
- Kendall County179
- Macon County178
- Logan County175
- Piatt County175
- Kankakee County175
- Bureau County171
- Henry County170
- Peoria County169
- Crawford County168
- Mercer County167
- Livingston County167
- DeWitt County166
- Grundy County165
- Clark County163
- Shelby County162
- Christian County161
- Coles County161
- DeKalb County161
- Whiteside County160
- Edgar County159
- Jasper County159
- Knox County158
- Lake County158
- Clay County155
- Putnam County154
- Iroquois County154
62 more counties
- Douglas County152
- Marshall County150
- Moultrie County150
- Wabash County150
- Hancock County148
- Ford County147
- Lawrence County146
- Menard County146
- Lee County146
- Alexander County146
- Effingham County143
- Winnebago County143
- Jo Daviess County141
- Henderson County140
- Cumberland County140
- Stark County140
- Stephenson County138
- Edwards County138
- Pulaski County137
- White County135
- McDonough County134
- Ogle County134
- Wayne County132
- Richland County131
- Boone County130
- Union County130
- McHenry County129
- Cass County128
- Carroll County127
- Warren County126
- Morgan County126
- Jackson County126
- Madison County125
- Massac County123
- Pope County121
- Jefferson County120
- Gallatin County117
- Franklin County116
- Hamilton County116
- Perry County116
- Fayette County116
- Johnson County115
- Williamson County115
- Saint Clair County113
- Pike County113
- Adams County111
- Calhoun County109
- Schuyler County107
- Clinton County107
- Saline County105
- Hardin County103
- Marion County103
- Monroe County96
- Macoupin County96
- Jersey County95
- Scott County94
- Washington County93
- Bond County92
- Randolph County90
- Brown County89
- Montgomery County87
- Greene County84
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Sources
National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.