A measure of how cold the atmosphere feels, taking not just actual temperature into account, but also wind, which can make the air considerably colder
(Meteoroloji) Wind chill (often popularly called the wind chill factor) is the felt air temperature on exposed skin due to wind. The wind chill temperature is never higher than the air temperature, and the windchill is undefined at the higher temps (above 10 °C [50 °F]). Humidity on the skin can result in a higher felt air temperature, which is accurately termed the heat index (or humidex), and is used instead
the cooling effect of the wind. Still-air temperature that would have the same cooling effect on exposed skin as a given combination of temperature and wind speed. As the wind speed increases, the wind chill equivalent temperature decreases; e.g., an air temperature of 30 °F (-1.1 °C) with a wind speed of 20 mph (32.2 kph) produces a wind chill of 17 °F (-8 °C). Wind chill is often included in weather reports to describe how cold it feels