Frostbite Time Calculator
Wind strips heat from exposed skin faster than still air, so a cold day with wind feels far colder and can freeze skin quickly. The National Weather Service wind chill formula turns temperature and wind speed into an apparent temperature, and its chart marks zones where frostbite can occur in 30, 10, or 5 minutes. Enter the air temperature in Fahrenheit and the wind speed in miles per hour, and this calculator returns the official wind chill and the frostbite risk band your conditions fall into.
Wind chill formula
WC = 35.74 + 0.6215 x T - 35.75 x V^0.16 + 0.4275 x T x V^0.16
T in degrees F, V in mph, valid for T <= 50 F and V > 3 mph
Frostbite bands: 30 min near -18 F, 10 min near -36 F, 5 min near -50 F
The formula is the NWS standard adopted in 2001. The frostbite-time bands are read from the official wind chill chart and describe how quickly exposed skin can freeze at the resulting wind chill.
Cold safety notes
- Wind chill applies to exposed skin, not to objects, which cannot cool below air temperature.
- The formula is valid only at 50 F or colder with wind above 3 mph.
- Cover all skin and limit exposure when wind chill is well below zero.
- Watch for numbness and pale, waxy skin, early signs of frostbite.
- Follow local NWS wind chill advisories and warnings.
Frostbite time: frequently asked questions
What is the wind chill formula?
The official National Weather Service wind chill, in use since 2001, is WC = 35.74 + 0.6215 x T - 35.75 x V^0.16 + 0.4275 x T x V^0.16, where T is air temperature in degrees Fahrenheit and V is wind speed in miles per hour. It applies at temperatures at or below 50 F and wind above 3 mph.
How does wind chill relate to frostbite time?
The NWS wind chill chart marks zones where frostbite can occur on exposed skin in 30 minutes, 10 minutes, and 5 minutes. These bands correspond to wind chill values around minus 18 F, minus 36 F, and minus 50 F respectively. This calculator reports the band your wind chill falls in.
When does the wind chill formula apply?
Wind chill is defined for air temperatures of 50 F or below and wind speeds above 3 miles per hour. Outside that range the concept does not apply, and the calculator notes that the air temperature itself is the relevant figure. Wind chill never exceeds the actual air temperature.
Does wind chill affect objects or only people?
Wind chill describes heat loss from exposed human skin, so it applies to people and animals, not to inanimate objects. A car or a water pipe cannot cool below the actual air temperature no matter how hard the wind blows; wind only speeds how fast it reaches that temperature.
How can I reduce frostbite risk?
Cover all exposed skin, limit time outdoors when wind chill is low, and watch for numbness or pale, waxy skin. In the 5-minute frostbite band, exposed skin can freeze very quickly. Seek shelter and warmth, and avoid alcohol, which impairs the body's response to cold.
Official sources
- NOAA National Weather Service: Wind Chill Chart.
- NOAA National Weather Service: Wind Chill (PDF).
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.