Environment Canada has issued an extreme cold warning for the areas of Greenstone, Manitouwadge, and Hornepayne.
Wind chill values are expected to drop overnight to around -40.
Areas further north, including Eabametoong and Webequie, are forecasted to have wind chill values approaching -50.
The extreme cold is expected overnight Thursday and into Friday morning, with temperatures becoming more moderate during the daytime hours.
Environment Canada states that the extreme cold weather will be of greater risk for young children, older adults, people with chronic illnesses, people working or exercising outdoors, and those without proper shelter.
Frostbite can develop within minutes on exposed skin, especially with wind chill, so cover up if you are out in the cold this evening.