Wind Chill Calculator

Calculate the wind chill 'feels like' temperature using the official NWS formula.

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Enter your values and click Calculate

Wind chill is the perceived decrease in air temperature felt on exposed skin due to the flow of cold air. Moving air strips away the thin layer of warm air your body produces, causing it to lose heat faster than it would in still air. This calculator uses the official National Weather Service (NWS) wind chill formula, adopted in November 2001 and used by meteorologists across the United States and Canada. The formula applies when the temperature is at or below 50°F and wind speed is at or above 3 mph — outside these conditions, wind chill is not officially calculated. The danger level labels are based on frostbite exposure times established by Environment Canada and the NWS. At extreme wind chills, exposed skin can develop frostbite in under two minutes. Dress in layers, cover exposed skin, and limit time outdoors when wind chill values fall below −20°F.

How It Works

This calculator uses the NWS wind chill formula introduced in November 2001: Wind Chill (°F) = 35.74 + 0.6215 × T − 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 formula was developed using human subjects walking on a treadmill in a wind tunnel, instrumented with sensors measuring heat loss from the face. It replaced the older Siple-Passel formula, which was based on how fast water froze in a cylinder — not representative of human physiology. The exponent 0.16 captures the diminishing returns of higher wind speeds: each additional mph of wind has less additional cooling effect at high speeds than at low speeds. The formula only applies when T ≤ 50°F and V ≥ 3 mph; in warmer or calmer conditions, the actual air temperature is the relevant figure.

Examples

Cold Winter Day
Temperature of 20°F with 15 mph wind.
Result: Wind chill ≈ 6°F — feels 14° colder. Increasing danger; dress in layers.
Dangerous Cold
Temperature of −10°F with 30 mph wind.
Result: Wind chill ≈ −40°F — extreme danger. Frostbite in under 5 minutes on exposed skin.
Mild Winter Morning
Temperature of 35°F with 10 mph wind.
Result: Wind chill ≈ 27°F — feels 8° colder. Little danger, but a hat and gloves are advised.

Frequently Asked Questions

What is wind chill and why does it matter?
Wind chill is the perceived temperature felt on exposed skin when wind is factored in. Moving air removes the thin layer of warm air your body produces at the skin surface, increasing the rate of heat loss. The faster the heat loss, the colder you feel — and the faster frostbite or hypothermia can set in. Wind chill does not change the actual air temperature, but it accurately describes the physiological risk to unprotected skin in cold, windy conditions.
Why does the formula only work below 50°F?
Wind chill describes the cooling effect of wind on skin. Above 50°F, the air itself is warm enough that wind actually helps cool the body (as with a fan on a hot day) — a very different physiological effect. The NWS formula was calibrated specifically for cold-weather conditions where heat loss from exposed skin is a safety concern. At temperatures above 50°F, the 'feels like' temperature (if needed) is better described by the heat index formula for hot and humid conditions.
How quickly can frostbite occur?
Frostbite risk depends on both temperature and wind. At a wind chill of −19°F to −28°F, frostbite can develop on exposed skin in as little as 10–30 minutes. At −29°F to −45°F, the risk rises to 5–10 minutes. Below −46°F wind chill, frostbite can occur in under 2 minutes. The face, ears, fingers, and toes are most vulnerable. Warning signs include redness, numbness, and a waxy or pale appearance. Cover all exposed skin and seek shelter immediately if conditions approach these thresholds.
Does wind chill affect inanimate objects like pipes or car engines?
No. Wind chill only affects objects that generate their own heat, like the human body. A metal pipe or car exposed to −20°F wind chill will eventually reach −20°F — the actual air temperature — not the wind chill temperature. Pipes freeze at the air temperature, not the wind chill value. However, high winds do accelerate how quickly an exposed object reaches ambient air temperature, which is why an engine block cools down faster on a windy day.