Windchill
The term "wind chill" goes back to the Antarctic explorer Paul Siple, who coined it a 1939 dissertation, "Adaptation of the Explorer to the Climate of Antarctica." During the 1940s, Siple and Charles Passel conducted experiments on the time needed to freeze water in a plastic cylinder that was exposed to the elements. They found that the time depended on how warm the water was, the outside temperature and the wind speed.
However in simple terms Wind Chill is the temperature it "feels like" outside and is based on the rate of heat loss from exposed skin die to the effect of wind and cold. The basis for calculation was changed in 2000 (using real people rather than plastic bottles ! - click here for a more detailed background) and is now calculated using the following formula
Wind chill temperature = 35.74 + 0.6215T - 35.75V (^0.16) + 0.4275TV(^0.16)
In the formula, V is in the wind speed in statute miles per hour, and T is the temperature in degrees Fahrenheit. Note: In the formula, ^ means the following term is an exponent (i.e. 10^(0.5 ) means 10 to the 0.5 power, or the square root of V).
Pictorially the formula can be seen as:
So for example if the temperature is -1C (=30F) and the wind is blowing at 15mph it really feels like -7C (=19F) - to convert fahrenheit just deduct 32 from the fahrenheit number and then multiply by 9/5.
If you would like to have more detailed calculations then click here to go to our special page of online calculator tools which will give you everything you need to know on temperature conversions (windchill, heat index, dew point etc.). However here's a couple of calculators that just relate to wind chill.
Firstly to convert Fahrenheit to Centigrade (or vice versa) just enter a number in either field, then
- click outside the text box, or
- press the tab key.