We are no stranger to handling cold air in the Tennessee Valley. It’s the wind that can make it very uncomfortable to be outside.
This brings to mind two words we hear a lot in the winter– wind chill and feels like temperature. These two indices are used interchangeably by many, but they are not exactly the same.
So what’s the difference?
It should be noted that the formula for calculating wind chill has not always been the same, but it remains surprisingly complex.
The formula for determining the wind chill? T(wc) = 35.74 + 0.6215T – 35.75(V0.16) + 0.4275T(V0.16), where T(wc) is the wind chill in degrees F, V is the wind speed in MPH, and T is the temperature in degrees F.
Despite the complexity of the equation, wind chill is not always an exact or particularly accurate measurement. Many times, humidity– an important factor in the comfort level of a cold airmass– and other factors such as sunlight are not included in the calculation.
The “feels like” temperature has been described as a slightly more accurate estimate of how it actually feels outside considering wind, humidity, and other factors– this is sometimes referred to as the ‘apparent temperature.’
The “feels like” method is based off an adult walking outdoors in the shade and also accounts for humidity.
The official definition is “the temperature, at the reference humidity level, producing the same amount of discomfort as that experienced under the current ambient temperature and humidity”.
It is valid over a wide range of temperatures and includes wind chill at lower temperatures.
The record for coldest wind chill in the world stands at 192 degrees below zero. This occurred in 2005 in Antarctica.