Scientists calculate wind chill by a mathematical formula that considers air temperature and wind speed. The National Weather Service and the Canadian Weather Service use one of the most common formulas for wind chill: Wind Chill = 35.74 + 0.6215T – 35.75(V^0.16) + 0.4275T(V^0.16). In this formula, T is the current air temperature in degrees Fahrenheit, and V represents the wind speed in miles per hour.
The National Weather Service adopted its current formula for calculating wind chill on November 1, 2001. Before 2001, the service used a formula that dated back to 1939. The newer formula is the result of increased scientific knowledge and of experiments that tested how fast the faces of volunteers cooled in a wind tunnel under various combinations of wind speed and temperature. Experts believe that the newer formula is better at describing the wind chill effect from a scientific perspective.
Wind chill is a naturally occurring phenomenon in which wind blowing across exposed skin draws heat away from the body. As the wind speed increases, the wind draws more heat away from the body, causing the body to cool more quickly than if there was no wind at all. This forms the basis for the current wind chill calculation formula, and explains how the wind chill effect is more drastic at higher wind speeds.