Three to four days of oppressive heat created hazardous conditions. From the 10th to the 12th, heat indices peaked at or above 105 degrees each afternoon. The oppressive heat started on the 9th along and west of a line from Mount Vernon to Metropolis. At the Carbondale airport, the highest heat index of this multi-day period was 108 degrees on the 10th. A rather strong southwest wind flow of hot and humid air prevailed between a slow-moving cold front over the Plains and a stationary high pressure center near the Carolina coast.

Heat in ALEXANDER, ILLINOIS
From 09-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in PULASKI, ILLINOIS
From 09-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in MASSAC, ILLINOIS
From 09-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in JOHNSON, ILLINOIS
From 09-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in UNION, ILLINOIS
From 09-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in WILLIAMSON, ILLINOIS
From 09-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in JACKSON, ILLINOIS
From 09-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Heat in PERRY, ILLINOIS
From 09-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in JEFFERSON, ILLINOIS
From 09-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in FRANKLIN, ILLINOIS
From 09-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in POPE, ILLINOIS
From 09-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in HARDIN, ILLINOIS
From 10-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in GALLATIN, ILLINOIS
From 10-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in SALINE, ILLINOIS
From 10-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in WHITE, ILLINOIS
From 10-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in HAMILTON, ILLINOIS
From 10-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in WAYNE, ILLINOIS
From 10-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in EDWARDS, ILLINOIS
From 10-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Heat in WABASH, ILLINOIS
From 10-AUG-21 11:00:00 to 12-AUG-21 18:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS