Environment Canada has put all of Southwestern Ontario under a Special Weather Statement, warning of humidex values in the low-to-mid thirties on Friday and Saturday.
Forecasters say temperatures should reach the upper twenties to low thirties by Friday afternoon, with the humidity making it feel closer to the mid-thirties.
Officials predict Saturday will be similar, with humidex values in the mid-thirties returning.
The national weather service says those values are still below the threshold required for a heat warning.
Environment Canada's alerts page can be found here.