As temperatures fall and the wind howls, we begin hearing about the danger of “wind chill.” The wind chill index combines the temperature and wind speed to tell you how cold the wind makes it “feel.” Even though the chill is given as a temperature, it’s not really a different kind of temperature. Low wind-chill numbers shouldn’t keep you from going out; they should encourage you to dress properly.
The NWS Windchill Temperature (WCT) index uses advances in science, technology, and computer modeling to provide an accurate, understandable, and useful formula for calculating the dangers from winter winds and freezing temperatures. The index:
- Calculates wind speed at an average height of five feet, typical height of an adult human face, based on readings from the national standard height of 33 feet, typical height of an anemometer
- Is based on a human face model
- Incorporates heat transfer theory, heat loss from the body to its surroundings, during cold and breezy/windy days
- Lowers the calm wind threshold to 3 mph
- Uses a consistent standard for skin tissue resistance
- Assumes no impact from the sun (i.e., clear night sky).
via NWS Wind Chill Index.