Environment Canada has issued a special weather statement as a hot a humid airmass has settled into the area.
All of midwestern Ontario is expected to experience daytime temperatures near 30 C, and humidex values in the high 30s Wednesday afternoon. It will be slightly cooler near the Great Lakes.
Overnight temperatures will fall to around 20 C, provided some relief from the daytime heat.
A cold front Friday night will bring in cooler temperatures and lower humidity for the weekend.
The special weather statement is in effect for Grey, Bruce, Huron, Perth, and Northern Wellington counties, as well as the Region of Waterloo, Northern Dufferin County, Barrie, Collingwood, and Hillsdale.
