Wind Chill Factor Calculator
Wind chill is the temperature it feels like when wind is factored into cold conditions. The National Weather Service (NWS) and Meteorological Service of Canada jointly adopted the current wind chill formula in 2001, replacing the older Siple-Passel equation. The new formula was developed from human clinical trials and is based on heat transfer theory. Enter the air temperature in degrees Fahrenheit and the wind speed in miles per hour. The calculator applies the official NWS equation and returns the wind chill temperature along with a frostbite risk estimate.
NWS 2001 wind chill formula
WC = 35.74 + 0.6215 × T - 35.75 × V0.16 + 0.4275 × T × V0.16
Where T is air temperature in degrees Fahrenheit and V is wind speed in mph. The formula is valid for T at or below 50 deg F and V of at least 3 mph.
Source: National Weather Service, NOAA, revised November 2001. Joint US-Canada formula developed with human volunteer trials at Defence Research and Development Canada.
NWS frostbite risk thresholds
- Wind chill above -18 deg F (-28 deg C): Low frostbite risk for most people with proper clothing.
- Wind chill -19 to -37 deg F (-28 to -38 deg C): Frostbite possible on exposed skin in 30 minutes.
- Wind chill -38 to -67 deg F (-39 to -55 deg C): Frostbite possible on exposed skin in 10 minutes.
- Wind chill below -68 deg F (-56 deg C): Frostbite possible on exposed skin in 5 minutes or less.
Wind chill calculator: frequently asked questions
What is wind chill?
Wind chill is the perceived decrease in air temperature felt by the human body due to the combined effect of cold air and wind. Moving air carries heat away from exposed skin faster than still air at the same temperature, making it feel colder than the actual thermometer reading.
What formula does this calculator use?
This calculator uses the NWS (National Weather Service) 2001 wind chill formula adopted jointly by the US and Canada: WC = 35.74 + 0.6215T - 35.75V^0.16 + 0.4275T x V^0.16, where T is air temperature in degrees F and V is wind speed in mph. This formula was developed from human trials and replaced the earlier Siple-Passel formula.
At what wind chill temperature does frostbite become a risk?
According to the NWS, frostbite can occur on exposed skin in 30 minutes at wind chills of -19 deg F (-28 deg C); in 10 minutes at wind chills of -38 deg F (-39 deg C); and in 5 minutes or less at wind chills below -68 deg F (-56 deg C). These thresholds are provided in the NWS Wind Chill Chart.
Does wind chill affect inanimate objects?
No. Wind chill only describes heat loss from warm bodies (people, animals) through convective cooling. Inanimate objects like pipes or car engines cannot cool below the actual air temperature from wind alone, although wind can speed up the time it takes to reach ambient temperature.
Is the wind chill formula applicable at high wind speeds?
The NWS formula is validated for wind speeds between 3 and 110 mph. At very low wind speeds (below 3 mph), the formula is less accurate. The formula also requires air temperatures at or below 50 deg F (10 deg C) to produce meaningful wind chill values.
Official sources
- NOAA National Weather Service, Wind Chill: weather.gov.
- NWS Wind Chill Temperature Index: weather.gov/lmk/windchill.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.