Chances are if you’ve been in tune with the weather lately, you’ve heard the term “wind chill,” “wind chill factor” or a more recent term, “real feel,” when describing daily forecasts.
Wind chill values indicate how cold people will feel outside based on the combined effects of temperature and wind. Normally, wind chill values are lower than the actual outside temperature because of the added effect of winds. This is why it’s often referred to as “real feel.”
Paul A. Siple (pronounced like disciple), who discovered the original formula for calculating wind chill in 1945, was from Erie, Pa. He was a geographer and Antarctic explorer who died at 59 in 1968.
He originally conducted studies on freezing water during a long night he spent near the South Pole. He based his calculations on how quickly water froze in plastic cylinders hung 33 feet from the ground, but critics contended that a more accurate wind chill formula should have been based on wind speed readings taken at “face level,” rather than at 33 feet.
Siple’s simple way of formulating wind chill values was in place for more than 50 years.
According to the National Weather Service, the methodology of figuring out the wind chill changed in 2001. The new wind chill formula is based on, among other things, wind speed readings calculated at 5 feet, or the average elevation of the human face. The new index also revised the calculations to account for body heat.
Wind chill values are commonly used to figure out how quickly frostbite will take effect on any exposed skin to the winter weather.