How is wind chill calculated?

Our bodies emit heat that normally stays in a thin envelope of warm air all around us. When the wind whisks away that warm layer, we lose heat faster — and that’s wind chill. The formula calculates the relationship between wind speed, air temperature and how cold you feel.

The wind chill concept came from two Antarctic explorers, Paul Siple and Charles Passel, back in the 1940s. They hung a plastic bottle of water on a clothesline and measured how long the water took to freeze under different conditions. Their measurements served as the basis for the first wind chill equation used by the National Weather Service, beginning in 1973 . . .

By 2000, better computers let a group of U.S. and Canadian scientists revise the equation — with the help of volunteers who walked through a wind tunnel with sensors on their bodies and faces. Both Canada and the U.S. began using the new — and far longer — equation a year ago.

Wind chill links:

To see a wind chill chart, try this link: http://www.nws.noaa.gov/om/cold/wind_chill.shtml

This site is good for background about wind chill: National Climate Data Center (National Oceanic and Atmospheric Administration)

Here’s another good site for wind chill background: National Weather Service (National Oceanic and Atmospheric Administration)

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