Wind Chill Calculator
Free wind chill calculator finds the 'feels like' temperature from air temperature and wind speed using the official NWS 2001 formula, in °F/mph or °C/km-h.
Updated 2026-06-14 · Free · No sign-up · Runs privately in your browser
Show the formula & steps
How the Wind Chill Calculator Works
Wind chill tells you how cold the air actually feels once wind is taken into account. Wind carries heat away from exposed skin faster than still air, so the perceived temperature drops. Enter the air temperature and wind speed (in °F/mph or °C/km-h), and the calculator returns the wind chill and the frostbite risk.
The Formula
This tool uses the official 2001 National Weather Service wind chill equation, which is calculated in imperial units:
WC = 35.74 + 0.6215·T − 35.75·V^0.16 + 0.4275·T·V^0.16
where T is the air temperature in °F and V is wind speed in mph. Metric inputs are converted to °F and mph, evaluated, then converted back to °C. The formula is valid only for T ≤ 50°F (10°C) and V ≥ 3 mph (4.8 km/h); outside that range the air temperature itself is reported.
Worked Example
For an air temperature of 20°F with a 20 mph wind:
- V^0.16 = 20^0.16 ≈ 1.591
- WC = 35.74 + 0.6215·20 − 35.75·1.591 + 0.4275·20·1.591
- WC ≈ 35.74 + 12.43 − 56.88 + 13.60 ≈ 4.9°F
So 20°F with a 20 mph wind feels like about 5°F.
Frostbite Risk by Wind Chill
| Wind chill (°F) | Frostbite time | Risk |
|---|---|---|
| Above 0 | Hours | Low |
| 0 to −18 | Possible | Moderate |
| −19 to −35 | ~30 min | High |
| −36 to −68 | ~10 min | Severe |
| −69 or lower | Under 5 min | Extreme |
Staying Warn in Wind Chill
- Cover all exposed skin — face, ears, fingers and nose freeze first.
- Wear windproof outer layers to block convective heat loss.
- Keep moving to maintain core temperature, but avoid sweating, which chills you further.
- Watch for numbness or waxy, pale skin, which are early signs of frostbite.
Frequently asked questions
What is wind chill?+
Wind chill is the 'feels like' temperature that accounts for how wind accelerates heat loss from exposed skin. Moving air strips away the thin layer of warmth around your body, so a windy 20°F day feels far colder than a calm 20°F day.
How is wind chill calculated?+
The current US/Canada standard is the 2001 NWS formula: WC = 35.74 + 0.6215T − 35.75·V^0.16 + 0.4275·T·V^0.16, where T is air temperature in °F and V is wind speed in mph. The result is the wind chill temperature in °F.
At what wind chill does frostbite happen?+
Frostbite on exposed skin can occur in about 30 minutes around a wind chill of −19°F, in roughly 10 minutes near −35°F, and in under 5 minutes at −69°F or colder. Cover exposed skin whenever the wind chill drops below freezing.
Does wind chill apply above 50°F?+
No. The wind chill index is only defined for air temperatures at or below 50°F (10°C) and wind speeds of at least 3 mph. Above those thresholds, wind has little cooling effect and the actual air temperature is used instead.
Does wind chill affect objects like car engines or pipes?+
No. Wind chill only describes how cold it feels to humans and animals losing body heat. Inanimate objects cannot cool below the actual air temperature, so a parked car or water pipe will not freeze faster because of wind chill alone, though wind does speed up reaching that air temperature.