Wind Chill Calculator
Calculate the wind chill temperature, how cold it actually feels based on air temperature and wind speed.
Wind chill makes a real difference for outdoor activity planning in winter. At 28°F with a 20 mph wind, the feels-like temperature is 13°F, a 15-degree gap that changes what you need to wear and how long you can safely stay outside. I check this before any extended outdoor activity in cold weather.
Wind chill only applies when the temperature is below 50°F (10°C). At higher temperatures, wind is cooling but does not produce the skin-chilling effect the formula models. The NWS formula requires wind speeds above 3 mph.
The NWS wind chill formula
The National Weather Service uses the 2001 revised wind chill formula: Wind Chill (°F) = 35.74 + 0.6215T − 35.75(V^0.16) + 0.4275T(V^0.16), where T is air temperature in °F and V is wind speed in mph. This formula was developed from human subject testing at the Defence Research Establishment in Manitoba, Canada, replacing the older Siple-Passel formula that had been used since 1945 and is now known to have overestimated wind chill.
What wind chill actually measures
Wind chill quantifies how quickly wind accelerates heat loss from exposed skin. In still air, your body warms a thin layer of air next to the skin. Wind disrupts and replaces this insulating layer continuously, increasing the rate of heat loss. The wind chill temperature is the still-air temperature that would cause the same rate of heat loss as the actual temperature-wind combination. It applies to exposed skin, properly insulated areas are not affected by wind chill in the same way.
Frostbite risk by wind chill
The NWS frostbite time estimates: at wind chill above 0°F, frostbite on exposed skin is possible in 30+ minutes. At −10 to −20°F wind chill, frostbite can occur in 10–30 minutes. At −20 to −30°F wind chill, frostbite in 5–10 minutes. Below −30°F wind chill, frostbite can occur in under 5 minutes. These are estimates for exposed skin, wet skin or poor circulation shortens the timeline significantly.
Frequently asked questions
Does wind chill affect how cold objects get?
No. Wind chill affects how quickly heat is removed from warm objects (like your skin). An inanimate object will cool to the actual air temperature but not below it, wind speed doesn't change the equilibrium temperature, only the rate of cooling. A car radiator or water pipe can freeze at 32°F regardless of wind speed.
Why doesn't wind chill apply above 50°F?
The wind chill formula models heat loss from skin warmer than the air. Above about 50°F, the wind-enhanced heat loss is still occurring but the effect is described differently, as cooling or evaporative cooling rather than dangerous wind chill. The NWS formula is only applied when both temperature is at or below 50°F and wind speed is above 3 mph.
What's the coldest wind chill ever recorded?
The record wind chill in the continental US was approximately −103°F wind chill at Mt. Washington, New Hampshire, on February 6, 2023, when the air temperature was −47°F with 127 mph winds. Antarctica has recorded wind chills below −140°F.