Wind Chill Calculator

Agarapu Ramesh — Editor and content reviewer
Editorially reviewed Reviewed by Agarapu Ramesh, science educator (chemistry). LinkedIn
Last reviewed: May 2026 | Standard temperature conversion formulas

What this calculator does

This wind chill calculator estimates how cold exposed skin feels when cold air is combined with moving wind. The number helps explain cold-stress risk by translating extra convective heat loss into a more intuitive feels-like temperature.

A calm winter day and a windy winter day can have the same thermometer reading but very different human effects. Wind strips away the thin layer of warmer air that forms near the skin, so the body loses heat faster. Wind chill is therefore a human heat-loss index, not a description of what happens to inanimate objects.

Inputs explained

  • Air temperature: Enter the actual air temperature in F or C.
  • Wind speed: Enter the wind speed and choose the correct speed unit when available on the page.
  • Unit selector: The calculator applies the correct U.S. or metric formula based on the temperature scale you use.

How it works / method

The page uses the standard wind chill formulas commonly associated with National Weather Service guidance. For U.S. units, the model is valid for temperatures at or below 50 F and wind speeds above 3 mph. For metric inputs, the matching cold-weather form is applied below 10 C with sufficiently strong wind. Outside those ranges, the model is intentionally treated as invalid because it was not built for mild weather.

Formula used

WCT(F) = 35.74 + 0.6215T - 35.75V^0.16 + 0.4275TV^0.16

For metric inputs, the calculator uses the equivalent Celsius form. T is air temperature and V is wind speed. The model is designed for exposed skin and open-air cold stress, not sheltered conditions or indoor environments.

Practical note: Wind chill is a rate-of-heat-loss indicator for people. It does not mean metal, car engines, or parked equipment become colder than the actual air temperature because of wind alone.

Calculates heat loss from exposed skin due to wind.

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Step-by-step example

Suppose the air temperature is 20 F and the wind speed is 20 mph. The dry air temperature is cold, but the human cooling rate becomes much more severe once wind is added.

  1. Enter 20 for temperature and choose F.
  2. Enter 20 for wind speed in mph.
  3. The result falls near 4 F as a wind chill value.
  4. That means exposed skin loses heat roughly like it would on a calmer day around 4 F.
  5. If clothing is wet or skin is exposed, frostbite risk rises faster than the thermometer alone suggests.

Use cases

  • Checking whether exposed outdoor work should be reduced, delayed, or paired with heavier cold-weather clothing.
  • Explaining forecast cold stress to runners, cyclists, utility crews, and winter travelers.
  • Comparing two winter forecast periods where the air temperature is similar but wind exposure is very different.
  • Teaching the difference between measured air temperature and a derived human-exposure index.

Assumptions and limitations

  • The wind chill model is only meant for cold-weather conditions inside its published validity range.
  • Shelter, sunshine, terrain, face coverings, moisture, and metabolic heat can all change how a person actually feels.
  • The result should not be used as a blanket trigger for all industrial or medical decisions without local safety protocols.
  • Wind chill does not account for solar radiation and is not a summer or warm-season comfort index.

For heat exposure, use heat index, apparent temperature, humidex, or WBGT instead of trying to interpret wind chill outside the cold-weather regime.

NOAA Wind Chill Calculator

Use noaa wind chill calculator or nws wind chill calculator for cold-weather apparent temperature. The NWS wind chill formula is defined for air temperatures at or below 50 F and wind speeds above 3 mph.

Frequently Asked Questions

The 2001 NWS-EC formula is the modern standard: WCT = 13.12 + 0.6215T − 11.37V0.16 + 0.3965TV0.16, with T in °C and V the wind speed in km/h. Valid for T ≤ 10°C and V ≥ 4.8 km/h. So at −10°C and 30 km/h wind, WCT ≈ −20°C. The Imperial form uses °F and mph with different constants. The 2001 formula replaced an older 1945 version that was based on a freezing-water beaker experiment and overstated the cooling effect.
Metric: WCT = 13.12 + 0.6215T − 11.37V0.16 + 0.3965TV0.16, T in °C, V in km/h. Imperial: WCT = 35.74 + 0.6215T − 35.75V0.16 + 0.4275TV0.16, T in °F, V in mph. Both come from the joint US-Canada 2001 revision based on tests with human subjects walking face-to-wind. They are valid only at low temperatures and meaningful winds. Below 4.8 km/h or above 10°C, just report air temperature — wind chill stops being a sensible concept.
Environment Canada bands: above −9 low risk, −10 to −27 risk of frostbite on prolonged exposure, −28 to −39 frostbite in 10–30 minutes, −40 to −47 frostbite in 5–10 minutes, −48 to −54 frostbite in 2–5 minutes, below −55 frostbite in under 2 minutes. Hypothermia risk grows in parallel. These are exposure times for bare skin on a healthy adult. Children, elderly, and people with circulation problems freeze faster. Always cover skin and check forecasts before extended outdoor work in winter.
Frostbite becomes a real risk when wind chill drops below −27°C. From −28 to −39 you have 10 to 30 minutes before exposed skin freezes. Below −40 the timer drops to under 10 minutes. Below −55 it takes under 2 minutes. These are guidelines for healthy adults — children, smokers, diabetics, and the elderly freeze faster because circulation to fingers, toes, ears, and nose is more easily compromised. Alcohol makes it worse by dilating peripheral blood vessels and accelerating heat loss.
Approximate frostbite onset times for exposed skin: above −28°C, low risk over hours; −28 to −39, 10–30 minutes; −40 to −47, 5–10 minutes; −48 to −54, 2–5 minutes; below −55, under 2 minutes. These come from US-Canada research underpinning the 2001 wind chill chart. Times shorten with prolonged exposure, wet skin, fatigue, alcohol, or any condition that cuts peripheral blood flow. Cover skin completely in serious cold, work in pairs, and watch each other for the white waxy patches that signal frostbite.
Plug into the Imperial formula: WCT = 35.74 + 0.6215(20) − 35.75(20)0.16 + 0.4275(20)(20)0.16. (20)0.16 ≈ 1.6, so WCT ≈ 35.74 + 12.43 − 57.2 + 13.69 ≈ 4.7°F. Round to 4°F. So 20°F air with 20 mph wind feels like roughly 4°F on bare skin — a 16°F drop. In metric, that is about −15.5°C felt at an air temperature of −6.7°C. Frostbite risk is low but exposed skin gets cold quickly. Cover face and ears.
Wind speeds up convective heat loss from the thin warm boundary layer that forms around your skin. With still air, that layer insulates you. With wind, it gets stripped continuously and replaced with cold air, so heat loss accelerates. The effect is bigger at lower temperatures and higher wind speeds, but it tapers — going from 30 to 60 km/h adds less drop than going from 5 to 30. Wind cannot cool you below air temperature; it only makes you reach it faster.
Wind chill is a human-physiology metric — it does not exist for inanimate objects. A pipe will cool to air temperature regardless of wind; wind only speeds up the rate of cooling. So if air is −15°C, the pipe eventually reaches −15°C with or without wind. Engine coolant, batteries, and metal cool faster in wind, which can matter for cold-start performance, but the final temperature is set by air temperature alone. Insulate pipes for the actual air temperature, not the wind chill number.

Sources & references

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