Definition
The apparent temperature felt on exposed skin, which combines the actual air temperature with the cooling effect of wind. As wind speed increases, heat is carried away from the body more quickly, making the air feel colder than a thermometer reading alone would suggest.
Plain English
How cold it actually feels when wind is blowing, compared to how cold the air really is. The stronger the wind, the colder it feels on your skin.
Context Anchor
Seen in cold-weather aviation weather, preflight planning, ramp operations, and survival planning after an off-airport landing.
Derivation
“Wind” means moving air, “chill” means coldness, and “factor” means something that contributes to a result. Together, the term points to wind as the added condition that makes cold air feel more severe to the body.
Why Pilots Care
Helps pilots assess risk of frostbite or hypothermia when working outside the aircraft in cold weather.
Grounding Statement
Standing beside the airplane on a cold morning with strong wind can cool your hands and face much faster than the same temperature on a calm day.
Intuition Check
Wind chill factor does not mean the air itself is colder, and it does not make the airplane, fuel, oil, or metal colder than the actual temperature. It describes how fast exposed skin loses heat in the wind.
Example Sentence 1
The temperature was only 20°F, but with a 25-knot wind across the ramp, the wind chill factor made it feel closer to 0°F during the preflight.
Example Sentence 2
The pilot checked the wind chill factor before preflighting to choose the right gloves and jacket.