While parts of the 2023 summer had warm to hot temperatures, it took until mid to late August for the combination of hot temperatures and higher humidity levels to build a heat wave. Excessive heat advisories and warnings were initially issued on Tuesday, August 22nd and lasted through Thursday, August 24th. Heat indices reached and exceeded 100 degrees each day, with overall highest heat indices occurring on Wednesday, August 23rd. During this time, maximum daytime heat indices reached 120 degrees in southwest Wisconsin at Fennimore (Grant County), Lancaster (Grant County), and the City of La Crosse (La Crosse County). Many sites from western into central Wisconsin recorded heat indices of 100 to 120 degrees over the three days from August 22nd to August 24th.

Excessive Heat in CRAWFORD, WISCONSIN
From 22-AUG-23 10:00:00 to 24-AUG-23 20:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

The combination of anomalously high temperatures and humidity on Tuesday, August 22nd and Wednesday, August 23rd resulted in maximum heat indices of 98 to 115 degrees across Crawford County. The maximum heat index reached 106 degrees on Tuesday in De Soto and 115 degrees on Wednesday at the automated weather observation station in Prairie Du Chien.

Excessive Heat in TREMPEALEAU, WISCONSIN
From 22-AUG-23 10:00:00 to 24-AUG-23 20:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

The combination of anomalously high temperatures and humidity on Wednesday, August 23rd resulted in maximum heat indices reaching 119 degrees at the automated weather observation station in the City of Trempealeau.

Excessive Heat in MONROE, WISCONSIN
From 22-AUG-23 10:00:00 to 24-AUG-23 20:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

The combination of anomalously high temperatures and humidity on Tuesday, August 22nd and Wednesday, August 23rd resulted in maximum heat indices of 98 to 114 degrees in parts of Monroe County. The maximum heat index reached 98 degrees on Tuesday and 114 degrees on Wednesday at the automated weather observation station in Sparta.

Excessive Heat in JUNEAU, WISCONSIN
From 22-AUG-23 10:00:00 to 24-AUG-23 20:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

The combination of anomalously high temperatures and humidity on Tuesday, August 22nd and Wednesday, August 23rd resulted in maximum heat indices of 96 to 115 degrees across Juneau County. The maximum heat index reached 98 degrees on Tuesday in Necedah and Mauston and 115 degrees on Wednesday in Mauston at the automated weather observation stations.

Excessive Heat in JACKSON, WISCONSIN
From 22-AUG-23 10:00:00 to 24-AUG-23 20:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

The combination of anomalously high temperatures and humidity on Tuesday, August 22nd and Wednesday, August 23rd resulted in maximum heat indices of 98 to 115 degrees across Jackson County. The maximum heat index reached 100 degrees on Tuesday and 115 degrees on Wednesday at the automated weather observation stations in Black River Falls.

Excessive Heat in VERNON, WISCONSIN
From 22-AUG-23 10:00:00 to 24-AUG-23 20:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

The combination of anomalously high temperatures and humidity on Tuesday, August 22nd and Wednesday, August 23rd resulted in maximum heat indices of 99 to 116 degrees across Vernon County. The maximum heat index reached 101 degrees on Tuesday and 116 degrees on Wednesday at the automated weather observation station in Viroqua.

Excessive Heat in RICHLAND, WISCONSIN
From 22-AUG-23 10:00:00 to 24-AUG-23 20:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

The combination of anomalously high temperatures and humidity on Wednesday, August 23rd resulted in maximum heat indices reaching 116 degrees.

Excessive Heat in LA CROSSE, WISCONSIN
From 22-AUG-23 10:00:00 to 24-AUG-23 20:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The combination of anomalously high temperatures and humidity on Tuesday, August 22nd and Wednesday, August 23rd resulted in maximum heat indices of 101 to 120 degrees across La Crosse County. The maximum heat index reached 108 degrees on Tuesday and 120 degrees on Wednesday at the automated weather observation station in the City of La Crosse.

Excessive Heat in BUFFALO, WISCONSIN
From 22-AUG-23 10:00:00 to 24-AUG-23 20:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

The combination of anomalously high temperatures and humidity on Wednesday, August 23rd resulted in maximum heat indices reaching 114 degrees.

Excessive Heat in GRANT, WISCONSIN
From 22-AUG-23 10:00:00 to 22-AUG-23 20:00:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The combination of anomalously high temperatures and humidity on Tuesday, August 22nd and Wednesday, August 23rd resulted in maximum heat indices of 100 to 120 degrees across Grant County. The maximum heat index reached 106 degrees on Tuesday in Muscoda and 120 degrees on Wednesday at the automated weather observation stations in Fennimore and Lancaster.