Wind Chill Calculator
Find the apparent 'feels-like' temperature when wind is factored into cold air conditions. Ideal for meteorologists, hikers, and anyone dressing for winter weather.
About this calculator
Wind chill describes how cold the air feels on exposed human skin due to the combined effect of low temperature and wind speed. Moving air accelerates heat loss from the body by continuously replacing the thin warm layer of air near the skin. The formula adopted by Environment Canada and the US National Weather Service in 2001 is: WC = 13.12 + 0.6215 × T − 11.37 × V^0.16 + 0.3965 × T × V^0.16, where T is the air temperature in °C and V is wind speed in km/h. The result is the wind chill temperature in °C — always colder than or equal to the actual air temperature. The formula is empirically derived from human face heat-loss experiments and is valid for temperatures at or below 10 °C and wind speeds above 4.8 km/h. Below −27 °C wind chill, frostbite can occur within 30 minutes.
How to use
Scenario: Air temperature T = −10 °C, wind speed V = 30 km/h. Step 1 — Compute V^0.16: 30^0.16 ≈ 1.874. Step 2 — Plug into the formula: WC = 13.12 + (0.6215 × −10) − (11.37 × 1.874) + (0.3965 × −10 × 1.874). Step 3 — Evaluate each term: 13.12 − 6.215 − 21.307 − 7.430 = −21.83 °C. The wind chill temperature is approximately −21.8 °C, meaning your skin loses heat as fast as it would in still air at −21.8 °C — nearly 12 degrees colder than the thermometer reads.
Frequently asked questions
What is the difference between wind chill temperature and actual air temperature?
Actual air temperature is the thermodynamic temperature of the atmosphere measured by a sheltered thermometer, unaffected by wind. Wind chill temperature is a calculated index representing the rate of heat loss from exposed human skin — it is not a physical temperature of the air itself. Wind chill is always equal to or lower than air temperature because wind cannot cool an object below the ambient air temperature. On a calm day the two values are equal; as wind speed rises, the gap widens significantly.
How dangerous is a wind chill of minus 30 degrees Celsius?
A wind chill index of −30 °C represents a serious frostbite risk: exposed skin can freeze in 10–30 minutes depending on the exact conditions and individual physiology. Health authorities recommend covering all exposed skin, wearing moisture-wicking base layers, and limiting time outdoors when wind chill falls below −27 °C. Wind chill below −45 °C is considered extreme — frostbite can occur in under 5 minutes and hypothermia risk rises sharply. Always check wind chill, not just air temperature, before outdoor winter activities.
Why is the wind chill formula only valid for temperatures at or below 10 degrees Celsius?
The formula models heat loss from exposed human skin, which is only accelerated by wind when the air is colder than skin temperature (approximately 33–35 °C for the face). Above roughly 10 °C air temperature, wind can actually feel pleasant or provide cooling comfort rather than dangerous chilling, so the wind chill index loses meaningful safety relevance. Additionally, the empirical coefficients in the formula were derived from experiments conducted in cold conditions; extrapolating them to warm temperatures produces inaccurate results. For hot weather, the Heat Index (Humidex) is the appropriate apparent-temperature metric.