Excessive Heat — Knox, Illinois

2023-08-20 to 2023-08-25 · Knox, Illinois

Event narrative

A prolonged stretch of dangerous heat and humidity occurred across the Midwest. Peak afternoon heat indices were near or over 110 degrees each day, and heat indices remained above 80 degrees overnight. The Galesburg Airport (KGBG) recorded a heat index over 110 degrees each day, with a maximum heat index of 128 degrees on Wednesday, August 23.

Wider weather episode

A strong heat dome over the Midwest resulted in a six-day stretch of dangerous heat and humidity, which began on August 20 and continued through August 25. High temperatures were routinely above 90 degrees, while afternoon dewpoints were near 80 degrees, resulting in heat indices exceeding 110 degrees. During the overnight hours, lows only fell into the upper 70s, keeping heat indices in the 80s.

Source: NOAA Storm Events Database, event_id 1121998. Narrative written by the NWS forecast office that issued the report.