A Heat Warning remains in place for Perth County.
Environment Canada says the heat and humidity is expected to continue through Thursday.
The weather agency says the daytime maximum temperatures will be 29 to 33 degrees, with humidex values reaching 37 to 42.
The nighttime minimum temperatures will be 20 to 22 degrees.
Hot and humid air can also bring deteriorating air quality and can cause the Air Quality Health Index to approach the high risk category.
