Christy's weather: What is wind chill and why is it important?

Wind chill and temperature are often used as synonyms when describing winter life in the North, when they do, in fact, mean very different things.

High wind chill values mean increased risk of frostbite

Wind chill and temperature are often used as synonyms when describing winter life in the North, when they do, in fact, mean very different things.

The term “wind chill” is dark horse in the field of meteorology, because it often leads to a skewed weather picture. But what does wind chill mean, and why is it important to know as a completely separate weather entity?

Wind chill refers to how cold the outside air feels on exposed skin, based on airflow over the body. To understand wind chill, you first have to explore how the body loses heat to its surroundings.

When you go outside, your warm body will lose heat to the cold air around you. The bigger the difference between your body temperature and the air temperature, the faster you will cool down.

(Environment Canada)

When you are outside on a calm day, your body effectively heats the cooler air around it, creating a thin layer of slightly warmer air against your skin. On a windy day, this boundary layer of air will be removed and replaced by the colder ambient air, cooling your skin faster. Your body, in turn, will generate more heat to try even harder to maintain a normal temperature. All of this will make it “feel” colder than it actually is.

The higher the wind speed outside, the faster your skin will cool to the ambient air temperature.

Regardless of the wind speed, a surface will not cool down to the wind chill in an area. That is why using a wind chill as an actual air temperature is inaccurate.

So why is wind chill so popular when reporting the weather, and why is it important to know?

Wind chill is important to know if you are spending an extended period of time outside in the cold. With high wind chill values, skin will freeze more rapidly, which increases your risk of frostbite. Frostbite can occur in minutes, and even in some cases within seconds.

About the Author

Christy Climenhaga

CBC Saskatchewan Meteorologist

Christy Climenhaga, CBC Saskatchewan's Meteorologist, covers weather for the province. Catch her forecast tonight at 6 on CBC Saskatchewan News.