An immense ridge of high pressure over the Central Plains and Mississippi Valley entrenched heat and high dewpoint air across the region, resulting in daily heat indices from 100 to around 120, with very little recovery during the overnight hours.

Excessive Heat in CLAY, IOWA
From 21-AUG-23 11:00:00 to 24-AUG-23 18:00:00 (CST-6)
Reported by: ASOS

Daily afternoon and evening heat indices ranged from 103 to 116 degrees with a maximum heat index of 116 degrees at an Automated Surface Observing System site near Spencer on August 22.

Excessive Heat in IDA, IOWA
From 21-AUG-23 11:00:00 to 24-AUG-23 18:00:00 (CST-6)
Reported by: Department of Highways

Daily afternoon and evening heat indices ranged from 100 to 110 degrees with a maximum heat index of 110 degrees at an Iowa Road Weather Information System site near Ida Grove August 24.

Excessive Heat in LYON, IOWA
From 21-AUG-23 11:00:00 to 24-AUG-23 18:00:00 (CST-6)
Reported by: AWOS

Daily afternoon and evening heat indices ranged from 106 to 124 degrees with a maximum heat index of 124 degrees at an Automated Weather Observing System site at Sheldon on August 22 and 114 degrees at a Minnesota Road Weather Information System site near Beaver Creek on August 21.

Excessive Heat in OSCEOLA, IOWA
From 21-AUG-23 11:00:00 to 24-AUG-23 18:00:00 (CST-6)
Reported by: Mesonet

Daily afternoon and evening heat indices ranged from 110 to 127 degrees with a maximum heat index of 127 degrees at a personal weather station near Ashton on August 22.

Excessive Heat in SIOUX, IOWA
From 21-AUG-23 11:00:00 to 24-AUG-23 18:00:00 (CST-6)
Reported by: AWOS

Daily afternoon and evening heat indices ranged from 108 to 125 degrees with a maximum heat index of 125 degrees at a personal weather station in Hawarden and 120 degrees at an Automated Weather Observing System site near Maurice on August 21.

Excessive Heat in O'BRIEN, IOWA
From 21-AUG-23 11:00:00 to 24-AUG-23 18:00:00 (CST-6)
Reported by: AWOS

Daily afternoon and evening heat indices ranged from 106 to 124 degrees with a maximum heat index of 124 degrees at an Automated Weather Observing System site at Sheldon on August 22.

Excessive Heat in PLYMOUTH, IOWA
From 21-AUG-23 11:00:00 to 24-AUG-23 18:00:00 (CST-6)
Reported by: RAWS

Daily afternoon and evening heat indices ranged from 107 to 125 degrees with a maximum heat index of 125 degrees at a RAWS site near Westfield on August 21 and 118 degrees at an Automated Weather Observing System site at Le Mars on August 23.

Excessive Heat in WOODBURY, IOWA
From 21-AUG-23 11:00:00 to 24-AUG-23 18:00:00 (CST-6)
Reported by: ASOS

Daily afternoon and evening heat indices ranged from 104 to 121 degrees with a maximum heat index of 121 degrees at an Automated Surface Observing System site near Sioux City on August 21 and 115 degrees at an Iowa Road Weather Information System site near Moville on August 24.

Excessive Heat in DICKINSON, IOWA
From 21-AUG-23 11:00:00 to 24-AUG-23 18:00:00 (CST-6)
Reported by: Mesonet

Daily afternoon and evening heat indices ranged from 105 to 123 degrees with a maximum heat index of 123 degrees at personal weather stations near Milford, Terril, and Spirit Lake on August 22-23.

Excessive Heat in CHEROKEE, IOWA
From 21-AUG-23 11:00:00 to 24-AUG-23 18:00:00 (CST-6)
Reported by: AWOS

Daily afternoon and evening heat indices ranged from 106 to 116 degrees with a maximum heat index of 116 degrees at an Automated Weather Observing System site at Cherokee on August 21.

Excessive Heat in BUENA VISTA, IOWA
From 21-AUG-23 11:00:00 to 24-AUG-23 18:00:00 (CST-6)
Reported by: AWOS

Daily afternoon and evening heat indices ranged from 106 to 116 degrees with a maximum heat index of 116 degrees at an Automated Weather Observing System site near Storm Lake on August 22, and 109 degrees at an Iowa Road Weather Information System site near Rembrandt on August 24.