What does windchill mean?
Windchill is the apparent cooling produced when cold air moves across exposed skin. It describes how much colder conditions feel than the air temperature measured by a thermometer, as well as a numerical temperature or index calculated from wind speed and air temperature. The effect is greatest when strong winds combine with temperatures near or below freezing, because moving air removes warmth from the skin more rapidly than still air does. Windchill is important in forecasts, public safety warnings, aviation, and outdoor work because it can reveal a serious risk of frostbite or hypothermia even when the recorded air temperature seems relatively mild. The closed compound “windchill” is standard in both British and American English, although the two-word form “wind chill” is also widely used. The term is most often used for cold-weather conditions and should not be confused with the broader “apparent temperature,” a related measure that can also incorporate humidity.
nounThe cooling effect of wind on exposed skin, making the air feel colder than its measured temperature. The term can also refer to a calculated temperature or index based on air temperature and wind speed.
- The cooling effect of moving air on exposed skin.
- A calculated value expressing how cold conditions feel, based on air temperature and wind speed.
"With the temperature near freezing, the windchill made the exposed dock dangerously cold."
"Fierce winds produced a severe windchill across the open plain."
"The weather service issued a windchill advisory for the region."
Usually used as an uncountable noun, but the plural “windchills” can refer to distinct calculated values or conditions.
"The region recorded unusually low windchills during the storm."
Windchill can make a relatively mild day feel bitterly cold: the wind strips heat away from exposed skin faster than it can replace it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of windchill
Windchill is a compound formed in modern English from the established words “wind” and “chill.” “Wind” continues Old English wind, while “chill” developed from Old English ciele, meaning cold or chilly. The combined term became established in English during the twentieth century as descriptive language for the apparent cooling caused by wind.
Related word forms
How windchill is actually used
The open form “wind chill” is especially common in US English, while the closed form “windchill” is also standard and is frequently used as a modifier, as in “windchill advisory.” The term normally describes the effect of cold and wind on exposed skin and is distinct from the broader “apparent temperature,” which may also account for humidity.