Showing posts from February 14, 2016

What is the difference between the Old and New Wind Chill Formulas?

National Weather Service Windchill Chart Weather channels and news organizations are still making reference to the "old" wind chill formulas. Wind Chill describes the rate of heat loss on the human body resulting from the combined effect of low temperature and wind. As wind increases the internal body temperature is driven down at a faster fast, quickly reducing the exterior and interior body temperatures.   The "old" wind chill formula was first instilled in the 1940s and based on the research from Antarctic explorers Siple and Passel. The Siple and Passell formula was implemented through a series of observations on freeze times of plastic cylinders filled with water and placed in differing temperatures and wind speeds.  This old system did not take in consideration that the human body produces its own heat, unlike the plastic containers. In addition, weather stations measure wind speed, the basis for the WCT index , at a height of 33 feet where it is oft