Wind Chill Calculator: Feels-Like Temperature in Wind
Work out the wind chill from the air temperature and wind speed with the NWS 2001 formula, in °F or °C and mph or km/h. It applies at 50 °F (10 °C) or colder with winds of 3 mph or more.
- Wind chill
- -15 °F
About the Wind Chill Calculator
The Wind Chill Calculator shows how cold the air feels on bare skin when the wind blows. Wind strips away the thin layer of warm air next to your skin, so you lose heat faster than in still air at the same temperature. Type the air temperature in °F or °C and the wind speed in mph or km/h, and the calculator gives the wind chill in whole degrees, using the formula the US National Weather Service and Environment Canada adopted in 2001. The same page also works out the Heat Index and the Dew Point.
The formula is defined only for air at 50 °F (10 °C) or colder and winds of 3 mph (4.8 km/h) or more. Outside that range the calculator shows no wind chill and says why. The result is an estimate for a person walking into the wind in light conditions, not safety advice: dress for the actual forecast and follow your weather service's cold warnings.
How to use it
Steps
- Choose Wind chill.
- Type the Air temperature and pick °F or °C.
- Type the Wind speed and pick mph or km/h. Use the sustained wind speed from your forecast, not the gusts.
Switching a unit converts the number you typed, so the conditions stay the same.
The formula
With the air temperature in °F and the wind speed in mph at about 5 feet, the 2001 wind chill is
For metric readings, the calculator converts to °F and mph first, applies the formula, and converts the result back, using and 1 mph = 1.609344 km/h.
Worked examples
- 5 °F with a 20 mph wind: °F.
- 0 °F with a 15 mph wind: °F.
- -10 °C with a 20 km/h wind: °C.
- 50 °F with a 3 mph wind: 50 °F, the edge of the range, where the wind barely matters.
Wind chill and frostbite
The colder the wind chill, the faster exposed skin can freeze. Weather services warn that frostbite becomes possible within about 30 minutes once the wind chill reaches around -18 °F (-28 °C), and within minutes at much lower values. Cover your face, ears and hands in strong cold wind. Wind chill does not cool objects below the air temperature, so water still freezes only at 32 °F. To compare wind speeds in other units, use the Speed Converter.
Privacy
Nothing is uploaded; every calculation runs in your browser and never leaves your device. The readings you type stay on this page and are gone when you close or reload it.
Frequently asked questions
What is wind chill?
It is how cold the air feels on exposed skin when wind carries heat away faster. At 5 °F with a 20 mph wind, it feels like about -15 °F.
Which wind chill formula does the calculator use?
The formula the US National Weather Service and Environment Canada adopted in 2001: 35.74 + 0.6215T − 35.75V^0.16 + 0.4275TV^0.16, with T in °F and V in mph at about face height.
Why is there no wind chill above 50 °F?
The formula is defined only for 50 °F (10 °C) or colder and winds of 3 mph (4.8 km/h) or more. Outside that range it gives meaningless numbers, so the calculator shows none.
Can wind chill freeze water?
No. Wind chill describes how fast skin loses heat. Water and car radiators cannot cool below the actual air temperature, however strong the wind.
Does it work in Celsius and km/h?
Yes. Choose °C and km/h. The calculator converts to °F and mph, applies the formula, and converts the result back, so -10 °C with a 20 km/h wind feels like about -18 °C.