Extreme cold is measured differently in different parts of the country. Whenever temperatures drop dramatically below normal, staying warm and safe can become challenging. In general, your risk of health effects like windburn and frostbite increase at wind chill values below -27.
The wind can make cold temperatures feel even colder. The wind chill index measures what the temperature feels like on exposed skin based on the speed of the wind. A wind chill can cause your body to lose heat faster and your skin to freeze very quickly. Wind chills below -70 have been recorded in some northern Canadian communities.