Excessive Heat in Rock, Wisconsin

A hot air mass settled over southern Wisconsin to start the month of July, bringing 100-degree heat to many locations for multiple days between July 2nd and July 6th. While humidity levels were relatively low considering the temperatures, maximum heat indices still climbed to between 100 and 115 during the hot spell. Milwaukee and Madison each recorded two of the top-ten hottest days on record on July 4th and July 5th. Direct heat-related deaths included: a middle-aged man in Dane County, a middle-aged women in the city of Milwaukee and a middle-aged man in the city of Milwaukee. Additionally, indirectly-related heat fatalities occurred in Rock County and in Walworth County in which heat was a secondary cause of death. Based on news reports hundreds of people received medical treatment at hospitals or clinics due to heat-related illnesses, however, the exact number is unknown. These treated people were considered injured and a broad estimate of 300 was assigned to south-central and southeast Wisconsin.

The counties surrounding Dane had 4 days of 100 degrees or higher, while counties toward Lake Michigan had 2 or 3 days. The cites of Janesville, Kenosha, Middleton, Sullivan, and Paddock Lake topped out at 106 degrees, which was Wisconsin's highest temperature for the 2012 summer season. Numerous new daily record highs were set as well as record high minimums. The long duration of this excessive heat period makes this probably one of the four most dangerous heat waves to strike southern Wisconsin in recorded history.