Wind Chill Calculator
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What Your Result Means
- Wind Chill ("Feels Like" Temperature): The apparent temperature your exposed skin experiences due to wind stealing heat faster than still air. A 10°F day with 20 mph wind feels like −9°F.
- Frostbite Risk Level: Time to frostbite on exposed skin: Caution (90+ min), Moderate (30-90 min), High (10-30 min), or Severe (under 30 min). Risk depends on wind chill, exposure duration, clothing, and skin condition.
- Formula Applies Above 3 mph: Below 3 mph wind, air temperature is shown instead. The NWS formula was calibrated for winds at or above 3 mph.
How This Calculator Works
The 2001 National Weather Service formula combines air temperature and wind speed: 35.74 + 0.6215×T − 35.75×V^0.16 + 0.4275×T×V^0.16, where T is temperature in °F and V is wind in mph. The 0.16 exponent reflects how wind speed (rather than linearly) affects heat loss. Valid for temperatures below 50°F and winds of 3+ mph.
Quick Questions
What is wind chill?
Wind chill measures how fast wind removes heat from exposed skin. Still air at 10°F feels less harsh than windy 10°F, because wind accelerates heat loss. Wind chill is not a real temperature but an "apparent temperature" or "feels-like" value.
When was the NWS formula updated?
The current wind chill formula was adopted in 2001, replacing the 1945 formula. The update reflected improved science on how wind actually affects human skin cooling.
Does wind chill affect objects?
No. Wind chill only applies to living organisms with metabolic heat. Objects cool toward the actual air temperature regardless of wind chill. Wind does accelerate object cooling but is separate from "wind chill."
How is frostbite risk determined?
Frostbite exposure times come from medical research and NWS charts. Risk depends on wind chill, duration, and individual factors (age, clothing, health). The times are conservative estimates for unprotected skin.
Is wind chill the same as "feels like" temperature?
"Feels like" can include humidity, solar radiation, and other factors beyond wind chill. Wind chill focuses specifically on wind-driven heat loss from skin.
Sources
- NWS Wind Chill Chart — Official calculator and safety information
- NOAA — U.S. weather and climate data
- Environment and Climate Change Canada — Wind chill formula and guidelines
Method & review
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.