Windchill is the perceived decrease in temperature felt by the body due to the cooling effect of wind on exposed skin. Synonyms for windchill include wind chill factor, chill factor, wind chill index, cooling effect of wind, wind effect on temperature, perceived temperature, and apparent temperature. These terms all refer to the same phenomenon, which can make temperatures feel significantly colder than what is actually indicated on a thermometer. Windchill is an important factor to consider when planning outdoor activities or working in cold conditions, as prolonged exposure can lead to dangerous health effects such as hypothermia and frostbite.