Wind Chill Calculator

Calculate how cold it actually feels based on air temperature and wind speed with advanced weather analysis, frostbite risk estimation, and real-time thermal comfort insights.

Wind Chill Calculator

Enter air temperature and wind speed to get the wind chill temperature — what the air actually feels like to exposed skin once moving air strips away the warm boundary layer.

Quick scenarios

Air Temperature

°C

Temperature Unit

Wind Speed

km/h

Wind Unit

What Is Wind Chill?

Wind chill — sometimes called the wind chill index or wind chill equivalent temperature — is a measure of how cold the air actually feels to bare skin when wind is added to the picture. A thermometer in a sheltered box reports the air temperature, but exposed skin warms a thin boundary layer of air directly around it; the moment a breeze sweeps that buffer away, fresh cold air rushes in to take its place and your body has to work harder to keep up. The colder and faster that incoming air, the more heat your skin loses per minute, and the colder the conditions feel. A still −5 °C (23 °F) afternoon can be pleasant for a walk; a windy −5 °C with 40 km/h gusts feels like −15 °C (5 °F) and starts to bite within minutes.

This calculator uses the same wind chill formula the U.S. National Weather Service and Environment Canada adopted in 2001, calibrates it for any combination of common temperature and wind units, and layers in frostbite-time estimation, body heat-loss rate, and personalised safety guidance. Pair it with our heat index calculator for the warm-weather counterpart, the temperature converter for unit conversions, or the target heart rate calculator when planning cold-weather exercise.

How Wind Chill Works

Wind strips your warm boundary layer

Your skin heats a thin shell of air directly around it. Wind sweeps that warm shell away and replaces it with fresh cold air, so your body has to keep warming new air molecules — the faster the wind, the faster the heat drain.

Wind chill is a perceived temperature

Wind chill does not lower the air temperature itself — a glass of water outside still freezes at 0 °C regardless of wind. What changes is the rate at which exposed skin loses heat, so the wind chill value describes how that loss feels to a human.

Why the official formula was updated

The original 1945 Siple–Passel index over-estimated chill because it was calibrated on plastic cylinders rather than real skin. In 2001 the NWS and Environment Canada published a new model based on actual human physiological response — the formula this calculator uses.

What the formula assumes

The current wind chill equation assumes calm, dry, exposed skin at face height (1.5 m) on someone walking at about 5 km/h. It does not include solar radiation, humidity, or wet skin — for those, switch to the Feels-Like Temperature mode.

How to Use This Wind Chill Calculator

1
Pick a mode that matches your question
Wind Chill for the core number, Feels Like to add humidity and sun, Frostbite Risk for time-to-frostbite, Outdoor Safety Planner to factor an activity in, or Weather Exposure Analyzer for body heat-loss rate and total energy lost over a duration.
2
Enter air temperature and wind speed
Type the air temperature in °C, °F, or K and the wind speed in km/h, mph, m/s, knots, or ft/s. The calculator runs the official NWS / Environment Canada formula in the background regardless of which units you choose.
3
Add humidity, sun, exposure, or activity
The Feels-Like mode accepts relative humidity and sun exposure. Frostbite Risk and Weather Exposure Analyzer take an exposure duration. Outdoor Safety Planner takes the activity — your self-generated wind is added automatically.
4
Read the visual results
Press Calculate to see the wind chill gauge, frostbite meter, severity bar, weather analytics dashboard, comparison chart, intelligent safety insights, and tailored cold-weather recommendations.
5
Copy, share, or print the report
Use Copy to share the headline result, Share to send it to a friend, or Print to take a clean PDF / paper report into the field — useful for trip plans, work logs, and coaching prep.

Frostbite Risk Categories Explained

Safe

Above −10 °C · Above 14 °F

Conditions are tolerable for general outdoor activity. Standard winter clothing is enough; check on small children, the elderly, and pets after extended exposure.

Low Risk

−10 to −25 °C · 14 to −13 °F

Cold but manageable. Wear gloves, a hat, and layered clothing. Limit prolonged exposure for children and the elderly, and watch for early shivering.

Moderate Risk

−25 to −40 °C · −13 to −40 °F

Cover all exposed skin, wear a windproof outer shell, and warm up indoors every 20–30 minutes. Outdoor exercise should be brief and well-fuelled.

High Risk

−40 to −48 °C · −40 to −54 °F

Limit outdoor exposure. Wear insulated mittens, a balaclava, and goggles. Avoid metal contact with bare skin. Watch for numb cheeks, ears, fingers, and nose.

Severe Risk

−48 to −55 °C · −54 to −67 °F

Postpone non-essential outdoor activity. Hypothermia becomes a real danger. Travel only if absolutely necessary, in pairs, with emergency supplies.

Extreme Risk

Below −55 °C · Below −67 °F

Stay indoors. Any exposed skin freezes almost instantly. Travel only in an absolute emergency, and report your route and ETA to someone you trust.

Human Comfort Scale

A quick read of where the current wind chill sits on the human perception scale — from comfortable shirt-sleeve weather all the way down to dangerously cold conditions where any uncovered skin freezes within minutes.

🥵 Hot

Above 25 °C · Above 77 °F

Hot; wind has no warming effect.

😊 Comfortable

18 to 25 °C · 64 to 77 °F

Comfortable for most people in light clothing.

🙂 Cool

10 to 18 °C · 50 to 64 °F

Cool — a light jacket is usually enough.

🧥 Cold

0 to 10 °C · 32 to 50 °F

Cold — coat and gloves recommended.

🥶 Very Cold

−10 to 0 °C · 14 to 32 °F

Very cold — cover exposed skin.

❄️ Dangerously Cold

Below −10 °C · Below 14 °F

Dangerously cold — limit exposure and dress in layers.

Staying Safe in Extreme Cold

✓Cover every patch of exposed skin. Most frostbite cases involve cheeks, nose, ears, and fingertips — the areas people forget. A balaclava or buff plus liner mittens drop the risk dramatically.
✓Layer like a system, not a parka. Wicking base, insulating mid, windproof shell. You can vent the shell when you warm up and the base will keep moving sweat outward — a single fat coat traps damp at the skin.
✓Watch the wind, not just the thermometer. A 20 km/h wind doubles the perceived chill compared with a calm day. Use the wind chill, not the air temperature, to decide what to wear and how long to stay out.
✓Fuel and hydrate aggressively. Cold suppresses thirst even when you're losing fluid through breath, and shivering burns ~400 kcal/h. Carry warm fluid and high-calorie snacks; eat before you feel hungry.
✓Know the first signs of trouble. White or waxy patches on skin, numb fingers or toes, stumbling speech or coordination — any of these means get indoors, get warm, and dry off.
✓Plan turn-arounds before you leave. Decide a temperature and time at which you head back before the cold sets in. Wind chill peaks at dawn and again mid-afternoon in many climates — schedule around it.

Why Wind Chill Matters

Cold weather causes more weather-related deaths than heat in many countries, and the danger almost always comes from the combination of cold air and wind — not the thermometer reading on its own. A 0 °C (32 °F) afternoon is tolerable in a sheltered town centre; the same temperature on an exposed coastline with a 50 km/h sea breeze brings frostbite to ears and cheeks within an hour of inadequate clothing. Wind chill turns an abstract temperature into the actual heat-loss rate your skin experiences, which is the only number that matters when deciding how to dress.

For runners, cyclists, skiers, mountaineers, outdoor workers, delivery drivers, parents, and anyone whose day includes time outside in winter, wind chill is the decisive forecast variable. A reading in the Moderate band means "cover up and limit exposure"; in the Severe band it means "postpone non-essential outdoor activity"; in the Extreme band it means "stay indoors." Knowing where you are on that scale before you head out is the single most reliable way to avoid frostbite and hypothermia.

Cold Injury: Symptoms & Warning Signs

Frostnip

The earliest cold injury — skin turns white or pale, feels prickly or numb, but no permanent damage. Move indoors, warm the area against bare skin (not rubbing), and the colour returns in minutes. Frostnip is the warning that frostbite is one step away.

Frostbite

Skin becomes pale, waxy, or grey-yellow, hard or rubbery to the touch, and feels numb or absent of sensation. Common on cheeks, nose, ears, fingers, and toes. Do not rub or warm with direct heat — re-warm gradually in 38–42 °C water and get medical care; blistering and skin damage may follow.

Hypothermia (mild)

Vigorous shivering, cool skin, slurred speech, clumsy hands, slowed thinking. Core body temperature 32–35 °C. Move to shelter, remove wet clothing, insulate, and offer warm sugary drinks if the person is alert and able to swallow.

Hypothermia (severe)

Shivering stops, confusion or drowsiness, slow pulse and breathing, possible loss of consciousness — a medical emergency. Call emergency services, handle the person gently, insulate them from cold ground, and avoid sudden re-warming, which can cause cardiac arrest.

The Wind Chill Formula Explained

The current wind chill index was developed jointly by the U.S. National Weather Service, the Meteorological Service of Canada, the Joint Action Group for Temperature Indices (JAG/TI), and university physiologists, replacing the older 1945 Siple–Passel formula in November 2001. T is air temperature, V is wind speed measured at face height (1.5 m), and the constants are calibrated to actual human skin response.

Metric form

WCT = 13.12 + 0.6215 T − 11.37 V^0.16 + 0.3965 T·V^0.16

T in °C, V in km/h. Valid for T ≤ 10 °C and V ≥ 4.8 km/h. Used by Environment Canada.

Imperial form

WCT = 35.74 + 0.6215 T − 35.75 V^0.16 + 0.4275 T·V^0.16

T in °F, V in mph. Valid for T ≤ 50 °F and V ≥ 3 mph. Used by the U.S. NWS.

Siple–Passel heat loss

H = (10.45 + 10√V − V)(33 − T)

Body heat-loss rate in kcal · m⁻² · h⁻¹ with V in m/s and T in °C. Used to estimate exposure energy.

Wind Chill Safety Guidelines by Audience

🏃

Wind chill for athletes

Self-generated wind from running, cycling, and skating can double the effective wind chill. Start into the wind so the return leg is downwind, cover face and ears, and reduce intensity below −20 °C wind chill to avoid airway irritation and frost-nip on cheeks.

👷

Wind chill for outdoor workers

Many jurisdictions tie outdoor work / warm-up cycles to wind chill bands. Plan 10-minute warming breaks every hour below −25 °C wind chill, rotate tasks to keep fingers dexterous, and use buddy systems to spot pale cheeks and noses early.

🚴

Winter cyclists & commuters

Cycling is the harshest activity for wind chill — speed alone adds 20–30 km/h of apparent wind. Use lobster mittens, a windproof bib, and a balaclava under the helmet. Drop intensity below −15 °C ambient or postpone the ride.

🏔️

Hikers & mountaineers

Altitude drops air temperature ~6.5 °C per 1,000 m, and ridges concentrate wind. Calculate the wind chill at your turnaround time before you start, carry layered insulation, and rope into shelter early if a front comes in.

🐶

Children & pets

Children lose heat faster than adults; small dogs and short-haired breeds even faster. Limit outdoor play below −10 °C wind chill, use insulated coats and booties on dogs on salted ice, and never leave pets outside unattended in Severe or worse bands.

🚗

Drivers & travellers

Wind chill matters the moment you step out of the car. Keep an arctic survival kit (blanket, candle, food, water, shovel) in any winter vehicle, tell someone your route, and avoid travel in the Extreme band unless absolutely necessary.

Common Wind Chill Misconceptions

1
Wind chill freezes water faster
It does not — water freezes at the same temperature in still or windy conditions. Wind chill is a description of how cold the air feels to skin; objects can only cool down to the actual air temperature, no matter how hard the wind blows.
2
Wind chill is a 'real' temperature
Wind chill is a perceived temperature for exposed skin. Your phone screen, car engine, and water bottle don't feel the chill the way your face does. Use the air temperature for cold-soak engineering questions; use wind chill for people.
3
A heavier coat always solves it
A puffy coat without a windproof shell loses much of its insulation in a gust. Adding a thin windproof layer over normal clothing often does more than upgrading to a thicker insulator.
4
More wind always = more chill
Above ~70 km/h the marginal effect of additional wind on wind chill is small — the air boundary layer is already stripped. The risk above that wind speed becomes hypothermia from soaked, displaced clothing and projectile debris, not extra chill.
5
Indoors there's no wind chill
True in still indoor air, but a poorly sealed window, a fan, or a draft in an uninsulated garage all create a local wind chill effect. The same physics applies — moving cold air over skin transfers heat faster than still cold air.
6
Wind chill matters most when it's coldest
It actually matters most at moderate temperatures where people under-dress because the thermometer looks tolerable. Many frostnip injuries happen between −5 and −15 °C ambient with strong wind, not in the deep cold where everyone bundles up.

Built for runners, cyclists, skiers, mountaineers, outdoor workers, parents, and anyone facing winter cold.

Wind chill uses the U.S. National Weather Service / Environment Canada 2001 formula; apparent temperature uses the Australian Bureau of Meteorology AT model; body heat loss uses the Siple–Passel cooling equation; frostbite time uses the NWS / NOAA chart fit. See our methodology and editorial policy. This tool is for educational use only and is not a substitute for official cold-weather warnings or medical advice.

Frequently Asked Questions

Wind chill is the 'feels-like' temperature for cold weather — how cold the air actually feels to exposed skin once wind is added to the equation. Moving air strips away the warm boundary layer that skin generates, so the colder the wind and the faster it moves, the faster you lose heat and the colder it feels. A still −5 °C day can be comfortable for a walk; the same temperature with 40 km/h wind feels like roughly −15 °C and starts to bite within minutes.

This calculator uses the official 2001 wind chill formula from the U.S. National Weather Service and Environment Canada. In metric form it is WCT = 13.12 + 0.6215 T − 11.37 V^0.16 + 0.3965 T·V^0.16, with T in °C and V in km/h. The imperial form is WCT = 35.74 + 0.6215 T − 35.75 V^0.16 + 0.4275 T·V^0.16, with T in °F and V in mph. Both forms are mathematically equivalent and produce the same wind chill expressed in their respective units.

Your skin warms a thin layer of air directly around it — a kind of personal insulation blanket. Wind keeps replacing that warm shell with fresh cold air, so your body has to keep heating new air molecules and loses warmth faster than it would in still conditions. The stronger the wind, the faster the heat drain and the colder the same air temperature feels.

Air temperature is what a thermometer measures in a sheltered enclosure — it is independent of wind and describes the physical state of the air. Wind chill is a perceived temperature for exposed human skin: it describes how that air temperature feels to a person standing in moving air. Objects, like a glass of water, only cool down to the actual air temperature regardless of wind, but a human face loses heat much faster.

The 2001 wind chill model is calibrated to real human physiological response, measured on volunteers in controlled wind tunnels with skin-temperature sensors at face height. It is accurate to within a few degrees for healthy adults in typical clothing assumptions, but actual perception varies with body composition, acclimatisation, fitness, age, hydration, recent meals, and emotional state. Treat the wind chill as a planning value, not a precision measurement.

Frostbite happens when skin and underlying tissue freeze because heat loss outpaces the body's ability to maintain temperature in that area. It develops most often on exposed extremities — cheeks, nose, ears, fingers, and toes — where blood flow is already restricted in cold weather. Wet skin, tight clothing that cuts circulation, dehydration, alcohol, and fatigue all speed up the onset. Wind chill matters because it sets the rate at which skin loses heat in the first place.

At a wind chill near −28 °C (−18 °F), frostbite can begin in about 30 minutes on exposed skin. At −40 °C (−40 °F) the threshold drops to about 10 minutes, and at −48 °C (−54 °F) it can develop in as little as 5 minutes. Below −55 °C wind chill, exposed skin can begin to freeze in under 2 minutes — which is why most cold-weather safety guidance simply says 'no exposed skin' in that band.

Feels-like temperature is the broad term forecasters use for any apparent-temperature value — wind chill in cold weather, heat index in warm weather, and various blended formulas in between. The Australian Bureau of Meteorology apparent-temperature formula, which this calculator also reports, combines air temperature with humidity and wind so it is meaningful across the full temperature range, not just in the cold or heat extremes.

Wind chill becomes physically dangerous around −25 °C (−13 °F), where frostbite is possible within 30 minutes on exposed skin. Below −40 °C (−40 °F) frostbite is likely within 10 minutes, and below −48 °C (−54 °F) it occurs within 5 minutes. Most weather services issue wind chill advisories or warnings when sustained wind chill drops below those thresholds — and outdoor activity in those bands should be brief, well-protected, and ideally with a buddy.

Layer up with a wicking base, an insulating mid-layer, and a windproof shell. Cover cheeks, nose, ears, fingers, and any exposed wrists. Eat and drink more than you think you need — cold burns calories fast and suppresses thirst. Limit continuous outdoor exposure, warm up indoors regularly, watch for white patches on skin and stumbling speech, and tell someone your route and ETA before heading out. In Severe and Extreme wind chill bands, postpone non-essential outdoor activity entirely.

Wind Chill Calculator