On Weather blog, shows the forecasted heat indexes yesterday. Here in Madison the actual heat index was 119, because of a dew point of 86! It was a day when you didn't have to water the garden while working - just lean over the plants and let your sweat drip onto them. But I got some nice hollyhocks planted.
I spent ten years in Dallas and experienced many days hotter than this, but never a heat index this high - even I think during my years in St. Louis. Brutal.
Addendu: Oops, correction. It took me until now to realize that Paul Douglas was referring to Madison, Minnesota rather than Madison, Wisconsin. But it was also hot here.