- As the wind blows across a piece of exposed skin, it draws heat from the skin. This drives down skin temperature and eventually also lowers body temperature. Wind chill is therefore a way of describing how being exposed to a wind makes living things feel colder.
- Scientists Paul Sepple and Charles Passel carried out the first wind chill experiments in Antarctica by in 1941. They combined their own experiments with freezing water with the observations of expedition parties to produce a wind chill Index. This was essentially an estimate of heat transfer obtained by multiplying the wind chill factor by the difference between skin temperature and air temperature.
- Since those experiments, other scientists have worked to produce more accurate methods of calculating this natural phenomenon. Today, meteorologists in the United States, Canada and the United Kingdom use a method known as the JAG/TI algorithm, which measures "face only wind chill." This method is thought to be accurate since it has been clinically tested, is based on recent research and is relatively simple to use. It represents how the temperature would feel on your skin if the wind were at a walking pace of 4.8 km/h (just under 3 mph).
- In the United States, criteria governing when a wind chill advisory or warning is issued are decided on a local basis. For example, in the Rochester, New York, area, advisories are issued when the wind chill temperature is expected to fall to between 15 and 25 Fahrenheit. A warning is issued if the wind chill temperature is expected to fall below 25 Fahrenheit. Since wind chill indicates a felt temperature rather than an actual air temperature, it is always expressed without the word "degrees."
- It is important to pay attention to wind chill advisories and warnings because the effects of wind chill can be extremely dangerous. With a wind chill temperature of 18 Fahrenheit, exposed skin can freeze in 15 minutes.
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