Originally Posted by Bio300TDTdriver

"The original wind chill formula was derived from experiments conducted in 1939 by Antarctic explorers, Paul Siple and Charles Passel. These hardy scientists measured how long it took for water to freeze in a small plastic cylinder when it was placed outside in the wind. Over the years, the formula was modified somewhat, but remained based on the Antarctic experiments."


This formula was obsolete and in certain circumstances created confusion. Thus in april 2000 Environment Canada held an Internet Workshop [sic] on wind chill for it to be better adapted to reality. Rather than be based on a water cylinder, "the new index is based on a model of how fast a human face loses heat. We chose the face because it is the part of the body most often exposed to severe winter weather, assuming the rest of the body is clothed appropriately for the weather". Reading of the assumptions taken into account for this new index is relevant. Here is an example of these assumptions: "It [the wind chill] uses a calm wind threshold of 4.8 km/h; this value has been obtained by observing the speed at which people walk at intersections."

In case you want to read more: http://ptaff.ca/humidex/?lang=en_CA