## Wind Chill Factor

Wind chill factor was designed for a limited purpose. It measures heat loss from exposed areas of the human body, like hands and face, in low temperatures and measured wind speeds.

With this information, people venturing outside in exceptionally bitter weather would know an approximate time before exposed areas of the body would succumb to frostbite.

Wind chill factors are useful for temperatures at or below 50 degrees Fahrenheit and wind speeds above 3 miles per hour, though the subjectivity of how the weather “feels” makes wind chill factor an often disputed measurement tool.

## Wind Chill Formula

The new formula for wind chill factor was developed partly by experiment. Human subjects were wired for heat temperature loss as they walked in a cold wind tunnel.

Wind chill formula in English units of measurement:

Wind chill = 35.74 + 0.6215T – 35.75 (V^0.16) + 0.4275T (V^0.16)

• T = Temperature in degrees Fahrenheit (°F)
• V = Wind velocity in miles per hour (mph)

If using metric, the wind chill formula is:

Wind chill = 13.12 + 0.6215T – 11.37 (V^0.16) + 0.3965T (V^0.16)

• T = Temperature in degrees Celsius (°C)
• V = Wind velocity in kilometers per hour (kph)