The first day of the long weekend is forecast to be a steamy one for much of southern Ontario.
Environment Canada says that with high humidity added in, the region from Sarnia to Ottawa will bake in temperatures hovering near the 40° C mark.
The agency says high levels of ozone pollution that resulted in a smog advisory in several areas Friday will stick around for at least another day.
A smog advisory continues for several communities across southern Ontario, including: Hamilton, Halton and Peel regions, Sarnia, Waterloo and Windsor.
Health officials are encouraging residents to look out for relatives and friends who may be vulnerable to heat-related illness.
They're also advising everyone to drink lots of water, stay out of the sun and avoid physical activity during the hottest parts of the day.
During a smog episode, the Ontario Ministry of the Environment recommends:
The summer's scorching weather has led to several smog advisories across southern Ontario. Temperatures are expected to drop Sunday as cold winds blow in from the north.
With files from The Canadian Press