Wind Chill Calculator

Wind chill is the perceived temperature on exposed human skin when cold air and wind combine. Moving air strips away the thin warm layer that insulates your skin, making the air feel colder than a thermometer reads. A 30 °F day with 20 mph wind, for example, feels like 17 °F.

It uses the 2001 NWS formula: WC (°F) = 35.74 + 0.6215 x T - 35.75 x V^0.16 + 0.4275 x T x V^0.16, where T is air temperature in °F and V is wind speed in mph. The NWS defines this formula only for temperatures at or below 50 °F and wind speeds at or above 3 mph. The calculator still returns a value outside that range but flags it with a warning.

Frostbite risk climbs as wind chill drops, and this calculator tags it by wind chill value: increasing below 0 °F, high below -19 °F, and severe below -69 °F. The NWS notes that at a -19 °F wind chill, frostbite can develop on exposed skin in about 30 minutes; in the severe range it can happen in under 5 minutes. Actual frostbite time also depends on the specific temperature and wind, so treat these tiers as a guide.

No. Wind chill is defined only for living skin, which generates heat. Inanimate objects like pipes, car engines, or your windshield cool only down to the actual air temperature, never below it. Wind does speed up how fast they reach that temperature, but they cannot get colder than the surrounding air.

The NWS formula is defined only for temperatures at or below 50 °F and wind speeds at or above 3 mph. Above 50 °F, the body loses heat mainly through evaporation and radiation rather than convection, so the formula does not apply. Below 3 mph, wind chill is effectively the same as the air temperature, and the formula is not reliable there.