Hot and humid air currently building over the American Midwest will move into Southern Ontario on Tuesday.
Afternoon temperatures are expected to around 30°C or 86°F for much of Southern Ontario, resulting in humidex values easily surpassing the 40°C or 104°F threshold.
Environment Canada says the high humidex readings may make it feel like the hottest day of the summer, although breezy conditions should help alleviate the extreme heat. A very warm night is expected Tuesday night as well.
These hot and humid conditions are expected to ease on Wednesday.