Environment Canada has put an extreme cold warning into effect for London-Middlesex and Oxford counties.
With the wind chill, temperatures are expected to fall to nearly minus 30 on Saturday night.
The weather agency advised that people dress in warm layers, with the outermost layer being wind resistant.
“Watch for cold-related symptoms,” the agency said in a statement.
Things like shortness of breath, chest pain, muscle pain and weakness, numbness, and colour change in fingers and toes are effects of extreme cold weather.
“If it’s too cold for you to stay outside, it’s too cold for your pet to stay outside,” the statement reminded.
Temperatures are expected to rise on Sunday morning.
