How wind chill is calculated

In the winter, you probably often hear meteorologists refer to the wind chill factor or "feels like" temperature.

So what's wind chill?

It is the temperature it “feels like” outside and is based on the rate of heat loss from exposed skin caused by the effects of wind and cold. As the wind increases, the body is cooled at a faster rate causing the skin temperature to drop.

Wind Chill does not impact inanimate objects like car radiators and exposed water pipes, because these objects cannot cool below the actual air temperature

Here's how wind chill factor is calulated:

The NWS Wind Chill 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 does the following:

• Calculates wind speed at an average height of 5 feet, the 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 based on 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.

Wind Chill Temperature is only defined for temperatures at or below 50°F and wind speeds above 3 mph.

So is there an actual formula for wind chill?

YES.

Wind Chill = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16)

T is the air temperature in degrees Fahrenheit, and V is the wind speed in miles per hour.

Frostbite

The Wind Chill Chart below includes a frostbite indicator, showing the points where temperature, wind speed and exposure time will produce frostbite on humans. The chart above includes three shaded areas of frostbite danger. Each shaded area shows how long (30, 10 and 5 minutes) a person
can be exposed before frostbite develops. 

For example, a temperature of 0°F and a wind speed of 15 mph will produce a wind chill temperature of -19°F. Under these conditions, exposed skin can freeze in 30 minutes.