What is wind chill?
The most common answer to first part of that question would sound something along the lines of…”It is what the temperature feels like to us when the wind is blowing, and when it is cold outside”. To some degree, this statement is true.
But what is actually happening, in cold and windy weather, that makes us feel like it is colder than it actually is outside? And if it is just a “perception” why do “Wind Chill Warnings” even need to be issued?
If our bodies begin to lose heat faster than we can naturally produce it, particularly on a cold, Winter’s day-we shiver- a way of our muscles generating heat. Since wind is just the movement of air, wind itself is constantly affecting the temperature of the air that is contact with our skin!
Where does the “wind chill” number actually come from? How is it calculated?
Believe it or not, there is actually a formula for it, recently revised in 2001 by the National Weather Service. For all of the math nerds out there here it is:
T(wc) = 35.74 + 0.6215T – 35.75(V0.16) + 0.4275T(V0.16)
The “T” represents the actual air temperature, and the “W” represents the wind speed. Notice that the factors I discussed earlier have been put into this equation- to get the T(wc) the “Wind Chill Temperature”. Because heat loss is a primarily a concern in colder temperatures, Windchill Temperature is only defined for temperatures at or below 50 degrees F and wind speeds above 3 mph.