Extremely low wind chills, although dangerous, are not an actual temperature reading at all. They are a measure of the heat loss our body experiences when exposed to the wind. The colder the wind chill, the more dangerous it is.

Our body gives off a layer of heat that protects the skin from cold temperatures. A strong wind can blow this layer away from our skin, taking away our natural defense against the cold. Thus, the wind chill temperature is the temperature that our bodies will feel when our skin is exposed to the cold temperatures and the winds of winter.

Wind chill is a great predictor of such dangers as frostbite and hypothermia. Being exposed to below zero wind chills can induce frostbite within five minutes. While wind chills below minus 20 degrees can result in frostbite within a minute of exposure.

Wind chill was created for this exact reason. In the late 1930's, scientists at the South Pole needed to find a measurement to give them an idea of when the weather conditions became too dangerous for prolonged exposure. They conducted an experiment with two buckets of 100-degree water. One bucket was left out in the wind, while the other was sheltered. Similar to our body's skin, the bucket in the wind froze much faster as any heat it gave off was blown away from its surface.

The original formula was changed in 2001. Major changes were made to where the wind measurements were observed and the amount of skin a person might have exposed.

Originally, the wind chill scale was based on winds measured from wind sensors 33 feet above the ground. The winds blow considerably faster at this height than at the surface. The new wind chill calculation uses wind speeds 5 feet from the surface. Additionally, the new formula estimates for only a person's hands and face being exposed to the elements, rather than the whole body, which was used for the old scale.

Remember, when going outside in dangerous wind chills, covering exposed skin should be your main concern. But even with your skin covered, wind chills can still be dangerous when exposed to them for long periods of time. The best course of action is to stay inside when these conditions exist. If you need to go outside, remember to dress in layers and minimize skin exposure.