Wind Chill Calculator
Wind doesn't lower the air temperature — it strips away the thin layer of warm air your body heats around itself, so exposed skin loses heat faster and the cold bites deeper. Wind chill is the temperature calm air would have to be for that same rate of heat loss, and this calculator applies the official NOAA formula used in every winter weather bulletin.
The frostbite stat is the one worth knowing before a winter run or a scraped windshield: at a wind chill of −19°F exposed skin can freeze in 30 minutes, at −32°F in 10, and at −48°F in 5. The figure assumes night shade per NOAA — sunshine softens it a little, wet skin and clothing harden it a lot. It is the winter twin of the heat index: one formula, the whole story of what the weather will do to you.
How to use
- Pick your units (°F/mph or °C/km/h), then enter the air temperature and wind speed from any forecast.
- Read the feels-like wind chill in the big result, with the frostbite time estimate beside it.
- Share the figure in one tap — useful before commutes, dog walks and winter training sessions.
Frequently asked questions
How is wind chill calculated?
NOAA's formula: 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T·V^0.16, with T in °F and V in mph — a model of heat loss from a bare face in shade at night. It is defined for 50°F (10°C) and below with wind above 3 mph; outside that range, air temperature is the standard figure.
What wind chill causes frostbite?
Roughly −19°F wind chill freezes exposed skin in 30 minutes, −32°F in 10 minutes, and −48°F in 5. The calculator shows the estimate for your exact combination — cover extremities well before those thresholds, since fingers, toes and ears freeze first.
Can wind chill be lower than the actual temperature?
It always is, by definition — wind chill represents an equivalent temperature for heat loss, not the air itself. At 20°F with a 20 mph wind the calculator gives about 4°F: the air stays 20°F, your skin loses heat as if it were 4°F.
Why does calm air feel warmer than the wind chill number?
Below 3 mph the formula stops applying — your body's warm boundary layer stays mostly intact, and the air temperature is the honest figure. Indoors or behind a windbreak, dress for the thermometer; outside, dress for the wind chill.