How it works
Wind chill estimates how cold it feels on exposed skin when wind strips away the thin layer of warm air next to your body. This calculator uses the formula adopted by the U.S. National Weather Service and Environment Canada in 2001.
The index is defined only for air temperatures at or below 50 °F (10 °C) and wind speeds of 3 mph (4.8 km/h) or more. Wind speed is the standard reading at 10 m (33 ft) above ground, as given in forecasts.
Wind chill does not lower the actual temperature of objects. A car radiator or water pipe will not freeze unless the air itself is below freezing; it only cools to air temperature faster.
Formula
WC (°F) = 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T × V^0.16 (T in °F, V in mph)
Questions people ask
What is the wind chill at 0 °F with a 15 mph wind?
About −19 °F, matching the NWS wind chill chart. At that level, exposed skin can freeze in about 30 minutes.
Can wind chill freeze water above 32 °F?
No. Wind chill only describes heat loss from warm skin. Objects cannot cool below the actual air temperature.
When is a wind chill warning issued?
Criteria vary by region. In much of the northern U.S. an extreme cold warning (formerly wind chill warning) is issued around −25 °F to −35 °F wind chill.