Wind Chill Calculator
Input the temperature and wind speed to calculate the "feels like" index and detect potential frostbite weather danger.
Wind Chill Index Estimator
Measured at standard head height.
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Understanding Wind Chill and Frostbite Risk
A thermometer only measures the ambient air temperature, but the human body doesn't just feel ambient temperature—it feels the rate at which it is losing heat to the environment.
How Wind Removes Heat
Your body constantly generates heat, warming a thin layer of air just above your skin. When the air is calm, this insulating layer stays in place, keeping you relatively warm. However, when the wind blows, it constantly sweeps away that warm insulating layer, forcing your body to continuously expend energy to reheat the new cold air touching your skin. The higher the wind speed, the faster heat is drawn away.
Therefore, a 15°F day with 30 mph winds causes your body to lose heat as fast as it would on a calm -5°F day. This is what the "Wind Chill" or "Feels Like" temperature represents: it is an index of the heat loss rate.
The NWS Formula
The modern Wind Chill formula used by the National Weather Service (NWS) and Meteorological Service of Canada was updated in 2001. It mathematically models the heat loss of a human face walking into the wind. Very importantly, the NWS formula is only considered valid for temperatures at or below 50°F (10°C) and wind speeds above 3 mph (4.8 km/h). Above these temperatures, wind does not induce a chill significant enough to warrant a separate index.
Frostbite Danger Zones
Wind chill is a critical warning system for cold-weather exposure:
- -18°F (-28°C): Frostbite can occur in 30 minutes on exposed skin.
- -35°F (-37°C): Frostbite can occur in just 10 minutes.
- -60°F (-51°C): Extreme danger. Frostbite can occur in 5 minutes. Survival requires immediate specialized shelter.