A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Although the temperature rarely threatened climatological records, the humidity caused the heat index to reach extreme levels. The combination of heat and humidity led to several heat related illnesses across the region.

Excessive Heat in BROWN, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in MONTGOMERY, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in PIKE, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in MONROE, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in CLINTON, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in FAYETTE, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in GREENE, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in MACOUPIN, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in MADISON, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in MARION, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in RANDOLPH, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in WASHINGTON, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in CALHOUN, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in JERSEY, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in BOND, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region.

Excessive Heat in ADAMS, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region. The Quincy Airport reached a peak heat index of 116 on the 23rd.

Excessive Heat in ST. CLAIR, ILLINOIS
From 20-AUG-23 10:00:00 to 25-AUG-23 20:00:00 (CST-6)
Reported by: ASOS

A period of very hot and extremely humid weather began on Sunday, August 20 and lasted through Friday, August 25. Heat index values climbed to 110 to 120 degrees each day as measured by numerous reporting sites across the region. The Cahokia Airport reached a peak heat index of 122 on the 20th.