Alert archive / Illinois / Severe Thunderstorm Watches / 2026
Severe Thunderstorm Watches in Illinois, August 2026
12 severe thunderstorm watches in August 2026. An alert counts here when it covered any part of the state, so the counties below add up to more than the state. The archive of severe thunderstorm watches reaches back to 1997.
Severe Thunderstorm Watches by county
Each county as a circle sized by its count in August 2026. Tap one for its archive.
- Severe Thunderstorm Watches
- 12
- Busiest day
- August 10, 20262 severe thunderstorm watches
Over time
By day
Days in UTC, the clock the archive keeps.
The alerts
Every alert, in the order issued. Times are local, Central Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 7, 1:40 PM CDT | Severe Thunderstorm Watch | SPC | Rock Island | 8 hr |
| Aug 9, 9:46 AM CDT | Severe Thunderstorm Watch | SPC | Cook, DuPage, Lake, McHenry | 6 hr |
| Aug 9, 8:43 PM CDT | Severe Thunderstorm Watch | SPC | Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 28 more | 7 hr |
| Aug 10, 6:21 PM CDT | Severe Thunderstorm Watch | SPC | Cook, DuPage, Ford, Grundy, Iroquois, Kankakee and 2 more | 7 hr |
| Aug 11, 7:22 AM CDT | Severe Thunderstorm Watch | SPC | Boone, Bureau, Carroll, Champaign, Cook, DeKalb and 32 more | 6 hr |
| Aug 12, 6:41 AM CDT | Severe Thunderstorm Watch | SPC | Bureau, Champaign, Cook, DeKalb, DeWitt, DuPage and 31 more | 6 hr |
| Aug 12, 2:24 PM CDT | Severe Thunderstorm Watch | SPC | Edwards, Wabash | 5 hr |
| Aug 13, 5:47 AM CDT | Severe Thunderstorm Watch | SPC | Hancock, Henderson, McDonough, Mercer, Warren | 6 hr |
| Aug 13, 12:30 PM CDT | Severe Thunderstorm Watch | SPC | Champaign, Coles, DeWitt, Douglas, Edgar, Ford and 11 more | 6 hr |
| Aug 18, 2:48 PM CDT | Severe Thunderstorm Watch | SPC | Jo Daviess, Stephenson | 6 hr |
| Aug 19, 9:42 PM CDT | Severe Thunderstorm Watch | SPC | Alexander, Hardin, Johnson, Massac, Pope, Pulaski and 1 more | 7 hr |
| Aug 21, 2:57 PM CDT | Severe Thunderstorm Watch | SPC | Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 29 more | 9 hr |
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Cook County6
- DuPage County6
- Ford County6
- Iroquois County6
- Kankakee County6
- Livingston County6
- Rock Island County5
- Grundy County5
- McLean County5
- Mercer County5
- Tazewell County5
- Will County5
- Woodford County5
- Lake County4
- McHenry County4
- Bureau County4
- DeKalb County4
- Henry County4
- Jo Daviess County4
- Kane County4
- Kendall County4
- Knox County4
- LaSalle County4
- Lee County4
- Marshall County4
- Peoria County4
- Putnam County4
- Stark County4
- Stephenson County4
- Whiteside County4
- Boone County3
- Carroll County3
- Ogle County3
- Winnebago County3
- Champaign County3
- Henderson County3
- Vermilion County3
- Warren County3
- DeWitt County2
- Fulton County2
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.