What is the wind chill formula?

The NWS wind chill formula is: Wind Chill (F) = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16), where T is air temperature in Fahrenheit and V is wind speed in mph. This formula is valid for temperatures at or below 50F and wind speeds above 3 mph.

At what wind chill does frostbite occur?

Frostbite can occur in as little as 5 minutes when wind chill drops below -50F, within 10 minutes at -40F, within 30 minutes at -20F, and within 60 minutes at around 0F. Exposed skin is most vulnerable, especially fingers, toes, nose, and ears.

What is the difference between wind chill and actual temperature?

Actual temperature measures the air's thermal energy. Wind chill is a perceived temperature that accounts for how wind increases heat loss from exposed skin. Wind does not actually lower the temperature but makes it feel colder because it strips away the thin layer of warm air near your skin faster.

When is wind chill dangerous?

Wind chill becomes concerning below 0F, dangerous below -20F, and extremely dangerous below -40F. The NWS issues Wind Chill Advisories at -25F and Wind Chill Warnings at -35F or lower, as frostbite can occur rapidly at these levels.

Free Wind Chill Calculator — Frostbite Risk Index

Wind Chill Calculator

Calculate wind chill temperature, frostbite risk, and danger level using the official NWS wind chill formula.

Temperature Unit

Air Temperature (°F)

Wind Speed Unit

Wind Speed (mph)

Wind Chill Temperature

Low Risk

Conditions are relatively safe for brief outdoor exposure.

Wind Chill (°F)-- Wind Chill (°C)-- Frostbite Risk-- Danger Level--

Understanding Wind Chill and the NWS Formula

Wind chill describes how cold the air feels on exposed skin when wind is factored in. The National Weather Service (NWS) uses a wind chill formula developed in 2001 based on advances in science, technology, and computer modeling. It calculates the heat loss from exposed skin caused by wind and cold, providing a more accurate representation of how conditions feel than temperature alone.

The NWS Wind Chill Formula

The official formula is: Wind Chill (°F) = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16), where T is the air temperature in Fahrenheit and V is the wind speed in mph. This formula is valid when the temperature is at or below 50°F and wind speed is above 3 mph. Below these thresholds, the wind chill equals the actual air temperature.

Frostbite Risk Levels

Frostbite occurs when skin tissue freezes. The risk increases dramatically as wind chill drops. At wind chills of 0°F to -10°F, frostbite can occur within 30-60 minutes on exposed skin. At -20°F to -30°F, the risk window shrinks to 10-30 minutes. Below -40°F, frostbite can develop in as little as 5-10 minutes. Always cover exposed skin in cold, windy conditions.

This calculator supports both Fahrenheit and Celsius inputs as well as mph and km/h wind speeds, automatically converting between units. The danger level indicator provides quick guidance on the severity of conditions so you can take appropriate precautions before heading outdoors.

Wind Chill Danger Levels & Frostbite Risk

Wind Chill (°F)	Wind Chill (°C)	Danger Level	Frostbite Risk
32°F to 0°F	0°C to -18°C	Low	Unlikely with normal exposure
0°F to -10°F	-18°C to -23°C	Moderate	30-60 minutes on exposed skin
-10°F to -25°F	-23°C to -32°C	High (NWS Advisory)	10-30 minutes on exposed skin
-25°F to -45°F	-32°C to -43°C	Very High (NWS Warning)	5-10 minutes on exposed skin
Below -45°F	Below -43°C	Extreme Danger	Under 5 minutes; hypothermia likely

Source: National Weather Service. Cover all exposed skin and limit time outdoors when wind chill is below 0°F.

Wind Chill Calculator

Understanding Wind Chill and the NWS Formula

The NWS Wind Chill Formula

Frostbite Risk Levels

Wind Chill Danger Levels & Frostbite Risk

Frequently Asked Questions

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