Wind chill calculator
How cold it feels in the wind, and how soon frostbite can start.
About this calculator
This wind chill calculator shows how cold it feels on exposed skin when the wind blows. Enter the air temperature and wind speed.
It also shows how quickly frostbite can start, which helps when planning winter walks, runs or work outdoors.
How it works
Uses the wind chill formula adopted by the US and Canadian weather services in 2001: 35.74 + 0.6215T − 35.75V^0.16 + 0.4275TV^0.16, with T in °F and V in mph.
Last reviewed:
Worked example
- Units: °F, mph
- Air temperature: 20
- Wind speed: 15
Feels like: 6 °F (Low frostbite risk)
Common questions
What is wind chill?
How cold it feels on bare skin because wind carries body heat away faster. It doesn't make objects colder than the air temperature.
When is frostbite a risk?
Once the wind chill falls to about −28 °C (−18 °F), bare skin can freeze in 30 minutes. At −40 °C and below, it can take 10 minutes or less.
Does wind chill affect cars or pipes?
Wind cools things down to the air temperature faster, but never below it. So pipes freeze only if the air itself is below freezing.
Sources and further reading
The story behind it
Where the idea came from: In the 1940s, the Antarctic explorers Paul Siple and Charles Passel timed how fast water froze in the wind, creating the first wind chill index.
Their index was improved in 2001, using tests on volunteers' faces in a wind tunnel. Weather forecasts now report wind chill so people dress for how cold it really feels.
Why you can trust this calculator
- It runs in your browser. Nothing you type into it is sent anywhere.
- The method is explained on this page, so you can check it yourself.
- Free to use, with no sign-up.
- Results are estimates, so please double-check anything important.
- Spotted a mistake? Tell us and we'll look into it.
After 15 years as a mathematics educator, I built CalculStore to give students, teachers, professionals and anyone working with numbers simple, reliable tools.
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