Wind Chill Calculator

Enter the air temperature and wind speed to find the feels-like wind chill in both Fahrenheit and Celsius, using the official NWS formula.

°F
mph
Enter temperature and wind speed, then press Calculate.

The NWS wind chill formula

The United States National Weather Service uses a standard equation that combines air temperature and wind speed into a single feels-like number:

WC = 35.74 + 0.6215·T − 35.75·V^0.16 + 0.4275·T·V^0.16

Here T is air temperature in °F and V is wind speed in mph. The formula is valid when the temperature is 50°F or below and the wind is faster than 3 mph; outside that range the air temperature itself is the best estimate. To convert the result to Celsius, use C = (WC − 32) × 5/9.

Worked example

Air temperature 20°F with a 15 mph wind:

V^0.16: 15^0.16 ≈ 1.5341.
Plug in: 35.74 + 0.6215×20 − 35.75×1.5341 + 0.4275×20×1.5341.
= 35.74 + 12.43 − 54.84 + 13.12 = 6.45°F (≈ −14.2°C).
Why it feels colder: wind sweeps away the thin warm layer your body heats around your skin, so heat escapes faster. The thermometer still reads 20°F, but exposed skin behaves as if it were about 6°F.

Wind chill and frostbite

As wind chill falls, exposed skin freezes faster. The NWS warns frostbite can set in within about 30 minutes near −19°F and within roughly 10 minutes at −35°F or colder. In extreme cold, cover all exposed skin, limit time outdoors, and watch for numbness or pale, waxy skin. Wind chill is only defined for cold weather — in heat, the comparable measure is the heat index, which factors in humidity instead of wind.

Frequently asked questions

What is the wind chill formula?

The NWS formula is WC = 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T·V^0.16, with T in °F and V in mph. Valid at 50°F or below and wind over 3 mph.

What does wind chill actually measure?

The feels-like temperature on exposed skin. Wind removes the warm air layer next to your body so heat is lost faster, though the actual air temperature is unchanged.

At what wind chill is frostbite a danger?

Frostbite can occur in ~30 minutes near −19°F and in ~10 minutes at −35°F or colder. Cover exposed skin in extreme cold.

Does wind chill apply to warm weather?

No — it is only defined at or below 50°F. For hot weather the equivalent is the heat index, based on temperature and humidity.

MB
Mustafa Bilgic · Editor, Calcool
This tool uses the official US National Weather Service wind chill equation adopted in 2001. For active alerts and frostbite timelines, consult the National Weather Service. The calculator applies the formula to any temperature and wind you enter.

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