Wind Chill Calculator — What the Temperature Actually Feels Like
Calculate wind chill factor from air temperature and wind speed. Understand how wind accelerates heat loss and when cold weather becomes genuinely dangerous.
The thermometer says -5°C but the forecast mentions wind chill of -18°C. That gap isn't just a number — it represents a real difference in how fast your body loses heat. On a calm day, your skin warms a thin layer of air around you. Wind strips that layer away continuously, and your body has to work much harder to maintain temperature.
Calculate wind chill for any conditions at CalcHub.
The Wind Chill Formula
The current standard wind chill index (used by NOAA and Environment Canada since 2001):
T_wc = 13.12 + 0.6215T - 11.37V^0.16 + 0.3965T × V^0.16
Where T is air temperature in °C and V is wind speed in km/h. The formula was developed through human trials, measuring heat transfer from volunteers' faces in actual wind tunnel conditions.
Wind Chill Table
| Air Temp (°C) | Calm | 10 km/h | 20 km/h | 40 km/h | 60 km/h |
|---|---|---|---|---|---|
| 0°C | 0 | -3 | -5 | -8 | -10 |
| -5°C | -5 | -9 | -12 | -15 | -17 |
| -10°C | -10 | -15 | -18 | -22 | -25 |
| -15°C | -15 | -21 | -25 | -30 | -33 |
| -20°C | -20 | -27 | -32 | -37 | -41 |
| -25°C | -25 | -33 | -39 | -45 | -49 |
| -30°C | -30 | -39 | -46 | -52 | -57 |
Frostbite Risk
Wind chill doesn't directly cause frostbite — that requires actual tissue freezing. But high wind chill accelerates the rate at which exposed skin drops toward tissue-damaging temperatures.
| Wind Chill | Frostbite Risk on Exposed Skin |
|---|---|
| -10°C to -27°C | Low — takes 30+ minutes |
| -28°C to -39°C | Moderate — 10–30 minutes |
| -40°C to -47°C | High — in under 10 minutes |
| -48°C and below | Very high — in under 2 minutes |
How to Use the Calculator
- Enter air temperature in °C or °F
- Enter wind speed in km/h, mph, or m/s
- Get wind chill equivalent temperature and frostbite time estimate
Practical Protective Measures
Wind chill affects exposed skin, not insulated skin. A good windproof outer layer breaks the convective heat stripping almost entirely. Layering (moisture-wicking base, insulating mid-layer, windproof shell) prevents wind from ever reaching your skin. The wind chill number assumes bare skin — properly dressed for wind, the effective wind chill your body experiences is much closer to the air temperature.
Does wind chill affect objects and vehicles?
No — wind chill only applies to warm-blooded creatures that generate heat. Your car's engine coolant won't freeze faster on a windy day than a calm day at the same temperature. The freezing point of water is 0°C regardless of wind. Wind chill describes accelerated heat loss from warm surfaces, not reduced freezing points.
Why was the wind chill formula updated in 2001?
The older wind chill formula (developed in 1945 from Antarctic experiments) significantly overstated the effect — it assumed wind speeds at ground level rather than face height, and assumed unrealistically fast walking speeds. The 2001 formula was calibrated from actual human test subjects in controlled conditions, making it more accurate for real-world conditions.
Does humidity affect wind chill?
Humidity itself isn't factored into wind chill, but wet skin or wet clothing dramatically accelerates heat loss beyond what wind chill predicts. Being wet in cold wind is far more dangerous than being dry. This is why wool and synthetic fabrics that retain insulating properties when wet are preferred over cotton in cold environments.
Related Calculators
- Heat Index Calculator — the warm-weather equivalent of wind chill
- Dew Point Calculator — humidity's role in perceived temperature
- Humidity Calculator — relative humidity from temperature readings