Weather Math: The Wind Chill Factor

It's not the temperature, it's the WIND!

How do I calculate Wind Chill?

The wind chill is a measurement of what it "feels like" when wind speed is considered. We all know that wind can make a cool winter day feel bitter cold, and the wind chill is just a way of measuring this effect. The current formula for wind chill, set by the National Weather Service, is the following:

 

Wind Chill (Celsius, km/h)

$$ T_{chill}=13.12+0.6215*T_a-11.37*V^{0.16}+0.3965*T_a*V^{0.16} $$

In this formula, \(T_{chill}\) is the wind chill in celsius. \(T_a\) is the actual temperature. \(V\) is the wind velocity in km/h.

 

Wind Chill (Fahrenheit, mph)

To calculate the wind chill in fahrenheit, use the formula below. This formula uses mph for the wind speed.

$$ T_{chill}=35.74+0.6215*T_a-35.75*V^{0.16}+0.4275*T_a*V^{0.16} $$

 

More Information

The National Weather Service has a page that includes a chart of wind chill values for given wind speeds. There's also a wind chill calculator there. Or, visit Wunderground for a map of current US wind chill values.