The July 1-7, 2012 heat wave was arguably one of the Top-3 worst heat waves to affect Wisconsin in recorded weather history in terms of maximum temperatures and duration.
One has to go back to the July 12-14, 1995 heat wave to find a comparable heat wave. Due to mitigation efforts since the 1995 heat wave, only 24 fatalities were attributed to the 2012 heat wave – 18 direct and 6 indirect. The 1995 heat wave resulted in 154 heat-related fatalities. Additionally, the 2012 heat wave forced an estimated 350 people to seek medical treatment.
Wildlife specialists reported some fish and bird die-offs as water temperatures of inland lakes and rivers soared. Many ponds and marshes dried up. Buckled road pavements were noted and many cities/villages enacted burning and fireworks restrictions.
The peak of the heat wave was during the period of July 4-6th when maximum temperatures reached 105 to 106 at scattered locations in the southern half of the state. Heat index values peaked at 110 to 115. Many new daily record high temperatures and record high minimum temperatures were set - in excess of 3000. Some details are provided in the links below.
Ultimately, July 2012 was the warmest July for the continental U.S., blasting the Dust Bowl July of 1936. For Wisconsin July 2012 was tied for the 4th warmest on record.