How Wind Chill Is Calculated and What It Really Means
Wind chill is the temperature your skin feels when wind carries heat away. Here is the formula behind the number on a winter forecast.
What is the Wind Chill Calculator?
Wind strips away the warm layer of air around your skin, so a windy cold day feels colder than the thermometer says. The standard formula combines air temperature in degrees Celsius and wind speed in kilometres per hour, and it only applies when it is cold (10 degrees or below) and breezy enough (at least 4.8 km/h).
How to use it
- Enter the air temperature in degrees Celsius.
- Enter the wind speed in kilometres per hour.
- Press Calculate to see the wind chill temperature.
Worked example
Temperature 0 degrees C, wind 20 km/h: the tool gives a wind chill of about -5.24 degrees C.
What is the wind chill at 0 degrees with a 20 km/h wind?
It feels like about minus 5.24 degrees. Plugging 0 degrees and 20 km/h into the standard formula gives roughly minus 5.2, so the wind makes a freezing day feel several degrees colder on exposed skin. The formula is valid here because the temperature is at or below 10 degrees and the wind is above 4.8 km/h.
Frequently asked questions
Why does the formula refuse warm temperatures?
Wind chill describes extra cooling in cold air. Above 10 degrees the formula is not meaningful, so the calculator says so instead of giving a misleading number.
Does wind chill change how cold objects get?
No. Wind chill affects how cold exposed skin feels and how fast it cools, but inanimate objects only cool down to the actual air temperature, just faster.