Alert archive / Illinois / Heat Advisories / 2026
Heat Advisories in Illinois, August 2026
16 heat advisories 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 heat advisories reaches back to 2005.
Heat Advisories by county
Each county as a circle sized by its count in August 2026. Tap one for its archive.
- Heat Advisories
- 16
- Busiest day
- August 9, 20265 heat advisories
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 9, 12:29 AM CDT | Heat Advisory | PAH | Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more | 4 days |
| Aug 9, 1:05 AM CDT | Heat Advisory | LSX | Adams, Bond, Brown, Calhoun, Fayette, Greene and 5 more | 8 days |
| Aug 9, 1:41 AM CDT | Heat Advisory | DVN | Hancock, Henderson, Henry, McDonough, Mercer, Rock Island and 1 more | 18 hr |
| Aug 9, 2:03 AM CDT | Heat Advisory | ILX | Cass, Fulton, Knox, Mason, Menard, Morgan and 3 more | 17 hr |
| Aug 9, 2:03 AM CDT | Heat Advisory | ILX | Cass, Christian, Clark, Clay, Crawford, Cumberland and 12 more | 41 hr |
| Aug 10, 1:57 PM CDT | Heat Advisory | DVN | Hancock, Henderson, McDonough, Mercer, Warren | 30 hr |
| Aug 10, 2:34 PM CDT | Heat Advisory | ILX | Cass, Christian, Clark, Clay, Coles, Crawford and 16 more | 29 hr |
| Aug 12, 1:18 AM CDT | Heat Advisory | DVN | Hancock, Henderson, McDonough, Warren | 12 hr |
| Aug 12, 1:59 AM CDT | Heat Advisory | ILX | Cass, Christian, Clay, Crawford, Effingham, Jasper and 7 more | 18 hr |
| Aug 13, 12:32 AM CDT | Heat Advisory | ILX | Christian, Clark, Clay, Crawford, Cumberland, Effingham and 7 more | 4 days |
| Aug 30, 12:20 PM CDT | Heat Advisory | PAH | Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more | 47 hr |
| Aug 30, 12:23 PM CDT | Heat Advisory | ILX | Cass, Champaign, Christian, Clark, Clay, Coles and 29 more | 71 hr |
| Aug 30, 12:27 PM CDT | Heat Advisory | LSX | Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more | 3 days |
| Aug 30, 1:04 PM CDT | Heat Advisory | DVN | Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more | 6 days |
| Aug 31, 12:24 PM CDT | Heat Advisory | LOT | Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more | 33 hr |
| Aug 31, 12:24 PM CDT | Heat Advisory | LOT | Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more | 3 days |
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Morgan County6
- Sangamon County6
- Scott County6
- Cass County5
- Schuyler County5
- Christian County5
- Clay County5
- Crawford County5
- Effingham County5
- Jasper County5
- Lawrence County5
- Richland County5
- Shelby County5
- Hancock County4
- Henderson County4
- McDonough County4
- Warren County4
- Fulton County4
- Mason County4
- Menard County4
- Clark County4
- Cumberland County4
- Mercer County3
- Alexander County2
- Edwards County2
- Franklin County2
- Gallatin County2
- Hamilton County2
- Hardin County2
- Jackson County2
- Jefferson County2
- Johnson County2
- Massac County2
- Perry County2
- Pope County2
- Pulaski County2
- Saline County2
- Union County2
- Wabash County2
- Wayne County2
62 more counties
- White County2
- Williamson County2
- Adams County2
- Bond County2
- Brown County2
- Calhoun County2
- Fayette County2
- Greene County2
- Jersey County2
- Macoupin County2
- Marion County2
- Montgomery County2
- Pike County2
- Henry County2
- Rock Island County2
- Knox County2
- Coles County2
- Logan County2
- Macon County2
- Moultrie County2
- Boone County2
- Cook County2
- DeKalb County2
- DuPage County2
- Ford County2
- Grundy County2
- Iroquois County2
- Kane County2
- Kankakee County2
- Kendall County2
- Lake County2
- LaSalle County2
- Lee County2
- Livingston County2
- McHenry County2
- Ogle County2
- Will County2
- Winnebago County2
- Champaign County1
- DeWitt County1
- Douglas County1
- Edgar County1
- McLean County1
- Marshall County1
- Peoria County1
- Piatt County1
- Stark County1
- Tazewell County1
- Vermilion County1
- Woodford County1
- Clinton County1
- Madison County1
- Monroe County1
- Randolph County1
- Saint Clair County1
- Washington County1
- Bureau County1
- Carroll County1
- Jo Daviess County1
- Putnam County1
- Stephenson County1
- Whiteside County1
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.