🥶 Wind Chill & Dew Point Calculator

Wind chill quantifies how much colder the wind makes the air feel by stripping away the thin layer of warm air next to the skin. This calculator uses the formula officially adopted by the US National Weather Service (NWS) in 2001:

WC(°F) = 35.74 + 0.6215×T − 35.75×V^0.16 + 0.4275×T×V^0.16
(T = air temperature in °F, V = wind speed in mph)

Since the formula is defined in °F and mph, entering °C and km/h is automatically converted internally (°F = °C×9/5+32, mph = km/h×0.621371) before the formula runs, and the result is converted back to °C for display. The formula is only valid for T ≤ 50°F (10°C) and V ≥ 3 mph (4.8 km/h) — outside this range, wind produces negligible additional cooling.

Dew point is the temperature at which water vapor in the air begins to condense, and it is an absolute measure of how humid the air actually feels. The closer the dew point is to the air temperature, the muggier it feels. This calculator uses the Magnus-Tetens approximation with the Alduchov & Eskridge (1996) constants:

α(T,RH) = ln(RH/100) + (a×T)/(b+T)
Td = (b×α) / (a−α)
(a=17.62, b=243.12°C, T = temperature in °C, RH = relative humidity in %, Td = dew point in °C)

If you enter °F, it is converted to °C for calculation, and the resulting dew point is converted back to °F for display. A dew point above 15°C feels humid, above 20°C feels very muggy, and below 0°C indicates dry winter air.

The lower the wind chill, the higher the risk of frostbite on exposed skin. Approximate frostbite times based on the NWS wind chill chart:

For winter outdoor activity, wear several layers to trap warm air, and minimize exposed skin with a hat, gloves and scarf. Change out of wet clothing immediately, and avoid alcohol, which accelerates heat loss. Pale, numb fingertips, toes, ears or nose are early frostbite signs — move to a warm place immediately.