Excessive Heat in Chickasaw, Iowa

The combination of anomalously high temperatures and humidity resulted in maximum heat indices of 108 degrees on Tuesday, August 22nd and 118 degrees on Wednesday, August 23rd in New Hampton.

While parts of the 2023 summer had warm to hot temperatures, it took until middle 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 Monday, August 21st for select counties, expanding for all counties in northeast Iowa until 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 119 degrees at Decorah (Winneshiek County) and 118 degrees at Charles City (Floyd County) and Oelwein (Fayette County). Many sites in northeast Iowa recorded heat indices of 110 to 120 degrees over the four days from August 21st to August 24th.