A worked example
At 20°F with 15 mph wind, the wind chill is about 6°F — the temperature exposed skin loses heat at the same rate it would in 6°F of calm air.
Frequently asked questions
Why is wind chill not an actual temperature?
Wind chill represents how quickly exposed skin loses heat — not a physical thermometer reading. Two thermometers in the same spot, one sheltered from wind and one exposed, would show the same temperature; wind chill only describes the rate of heat loss from human skin.
Why does the formula only apply below 50°F and above 3 mph?
Below 50°F and with at least 3 mph of wind, heat loss from exposed skin is noticeably accelerated compared to calm air. Above those thresholds, the effect is negligible enough that quoting a wind chill number would be misleading.