Wind Chill Calculator

Wind chill is how cold the air feels on exposed skin once wind speed is combined with the air temperature. Wind strips away the thin warm layer next to your skin, so it feels colder than the thermometer reads even though the actual air temperature is unchanged.

It uses the National Weather Service 2001 wind chill index: WC = 35.74 + 0.6215 times T minus 35.75 times V to the 0.16 power plus 0.4275 times T times V to the 0.16 power, with T in Fahrenheit and V in mph.

It is defined for air temperatures at or below 50 F and wind speeds above 3 mph. The tool still computes a number outside that range and flags it with an amber note, since the result is not physically meaningful there.

Multiply the Celsius temperature by 9, divide by 5, then add 32 to get Fahrenheit. For example, -5 C is -5 times 9 divided by 5 plus 32, which is 23 F. Enter that value in the temperature field.

Divide the km/h figure by 1.609 to get mph, then enter that. A 24 km/h wind is about 15 mph. This tool expects miles per hour for the wind speed field.

No. Wind chill describes heat loss from warm skin only. Wind cannot cool an object below the actual air temperature, though it does make objects reach that temperature faster than still air would.

Frostbite can strike exposed skin within about 30 minutes when the wind chill reaches roughly -19 F, and within about 10 minutes near -35 F. Cover all skin and limit time outdoors in these conditions.

No. The temperature and wind speed you type are processed locally in your browser and never sent to a server, so you can run as many scenarios as you like privately.

For warm-weather comfort, try the heat index calculator, which combines temperature and humidity. The dew point and wet bulb calculators round out how muggy or muggy-dangerous the air feels.