🥶 Wind Chill Calculator: Feels-Like Temperature and Frostbite Risk
By Shihab Mia · Updated 2026-07-03
This wind chill calculator gives a general estimate of how cold the air feels and the rough frostbite risk to exposed skin. It is not medical or safety advice. Individual risk depends on clothing, skin condition, moisture, age, health and sun exposure, so treat the result as guidance only and follow official weather warnings and local advice.
This wind chill calculator turns a real air temperature and wind speed into the "feels like" value your skin actually experiences, using the official US National Weather Service formula. As a feels like temperature calculator it works in either Fahrenheit and miles per hour or Celsius and kilometres per hour, and it instantly shows the wind chill temperature in both units plus a frostbite risk note. It is a fast way to judge how dangerous the cold really is before you head outside.
What is the Wind Chill Calculator?
Wind chill is the temperature it feels like on exposed skin once moving air is taken into account. Your body constantly warms a thin layer of air right against your skin. Wind strips that warm layer away and replaces it with colder air, so heat leaves your body faster and you feel colder than a plain thermometer suggests. A wind chill calculator combines the two numbers that drive this, air temperature and wind speed, into a single feels-like figure so you can compare conditions honestly. The single number it produces is sometimes called the wind chill index, and it answers the everyday question of how cold does it feel with wind rather than what a bare thermometer reads.
The modern wind chill formula used by this calculator was introduced by the US National Weather Service and Environment Canada in 2001. It replaced an older 1945 model that badly overstated the effect. The current formula is based on measurements of heat loss from the human face at a height of about 1.5 metres, and it assumes calm-weather skin exposure with no direct sunshine. It is defined for air temperatures at or below 50 degrees Fahrenheit (10 degrees Celsius) and wind speeds above 3 miles per hour, which is exactly the range where wind chill matters.
There are two versions of the same equation, one for imperial units and one for metric, and this wind chill calculator runs whichever matches your input then converts the answer to the other unit for you. The imperial version takes temperature in Fahrenheit and wind in miles per hour; the metric version takes Celsius and kilometres per hour. Because wind speed enters through a fractional power, the first few miles per hour of wind cut the feels-like temperature sharply, then each extra unit of wind matters a little less. That is why a light breeze on a cold day can feel so much harsher than the still-air reading.
The reason to care is frostbite and hypothermia. When the wind chill drops low enough, exposed skin can freeze quickly: the NWS puts frostbite at roughly 30 minutes of exposure once the wind chill reaches about minus 18 degrees Fahrenheit, and at around 10 minutes near minus 30. Acting as a frostbite risk calculator, this wind chill calculator flags those thresholds automatically so you can decide whether a hat and gloves are enough or whether skin should simply stay covered. It does not account for wet skin, which freezes faster, so on damp or windy days treat the risk as slightly worse than shown.
A common point of confusion is that wind chill never changes the actual air temperature. Water, pipes, cars and thermometers cool down only to the true air temperature no matter how hard the wind blows; the wind just makes them reach it faster. Wind chill is strictly about how fast a warm object, such as a human body, loses heat. So the feels-like number from any wind chill calculator applies to living skin, not to freezing pipes or car radiators.
When to use it
- Checking how dangerously cold a winter morning really is before commuting, walking the dog or waiting for a bus.
- Deciding whether outdoor sport, running, cycling or a childrens game is safe or should be cut short.
- Judging how long exposed skin can stay uncovered on a ski trip, hike or hunt so you know when to add a face covering.
- Comparing two cold days that have the same thermometer reading but very different wind, to see which is actually harsher.
- Planning safe work breaks for anyone spending long periods outdoors in winter, such as delivery, construction or site crews.
- Teaching or learning how the NWS wind chill formula works with real, checkable numbers, using this NWS wind chill calculator to confirm chart values by hand.
How to use the Wind Chill Calculator
- Choose your units: Imperial (Fahrenheit and miles per hour) or Metric (Celsius and kilometres per hour).
- Enter the current air temperature from a thermometer or forecast.
- Enter the wind speed, ideally the sustained wind rather than a single gust.
- Press Calculate, or just edit a field, to see the wind chill feels-like value.
- Read the equivalent value in the other unit and the frostbite risk note beneath it.
- Use Copy result to save the feels-like figure and risk message for a message or log.
Formula & method
Worked examples
A commuter checks a 20 F morning with a steady 20 mph wind (imperial).
- Compute V^0.16 = 20^0.16 = 1.6382
- WC = 35.74 + 0.6215 x 20 - 35.75 x 1.6382 + 0.4275 x 20 x 1.6382
- WC = 35.74 + 12.43 - 58.57 + 14.01
- WC = 4.2 F, which the tool also shows as about -15.4 C
Result: Feels like 4.2 F. Cold but low frostbite risk, so a hat and gloves are enough.
A hiker faces 0 F air with a 15 mph wind (imperial).
- Compute V^0.16 = 15^0.16 = 1.5744
- WC = 35.74 + 0.6215 x 0 - 35.75 x 1.5744 + 0.4275 x 0 x 1.5744
- The two temperature terms are zero because T = 0
- WC = 35.74 - 56.28 = -19.4 F
Result: Feels like -19.4 F. Frostbite is possible on exposed skin in about 30 minutes, so cover the face.
A skier in Europe checks -5 C with a 30 km/h wind (metric).
- Compute V^0.16 = 30^0.16 = 1.7166
- WC = 13.12 + 0.6215 x (-5) - 11.37 x 1.7166 + 0.3965 x (-5) x 1.7166
- WC = 13.12 - 3.11 - 19.52 - 3.40
- WC = -13.0 C, shown by the tool as about 8.6 F
Result: Feels like -13.0 C. Uncomfortable cold; frostbite is possible with prolonged exposure.
Wind chill chart, feels-like temperature in Fahrenheit (NWS 2001 formula)
| Air temp \ Wind | 5 mph | 10 mph | 20 mph | 30 mph | 40 mph |
|---|---|---|---|---|---|
| 40 F | 36 | 34 | 30 | 28 | 27 |
| 30 F | 25 | 21 | 17 | 15 | 13 |
| 20 F | 13 | 9 | 4 | 1 | -1 |
| 10 F | 1 | -4 | -9 | -12 | -15 |
| 0 F | -11 | -16 | -22 | -26 | -29 |
| -10 F | -22 | -28 | -35 | -39 | -43 |
Frostbite risk on exposed skin by wind chill value
| Wind chill | Risk level | Time to frostbite |
|---|---|---|
| Above 0 F (-18 C) | Low | Frostbite unlikely for most people |
| 0 to -18 F (-18 to -28 C) | Increasing | Cover skin on long exposure |
| -18 to -30 F (-28 to -34 C) | High | About 30 minutes |
| -30 to -50 F (-34 to -46 C) | Severe | About 10 minutes |
| Below -50 F (-46 C) | Extreme | 5 minutes or less |
Common mistakes to avoid
- Thinking wind chill cools objects and pipes. Wind chill only describes how fast warm skin loses heat. Water, pipes and cars cool only to the true air temperature no matter the wind; the wind just gets them there faster. Do not expect a pipe to freeze below the actual air reading.
- Using gusts instead of sustained wind. The formula assumes a steady wind. A single strong gust does not represent the exposure your skin gets over minutes. Enter the sustained wind speed from the forecast for a realistic feels-like value.
- Applying it above 50 F or in near-calm air. The NWS formula is only defined for temperatures at or below 50 F (10 C) and wind above 3 mph. Outside that range it returns numbers that are not meaningful, which is why this tool flags out-of-range inputs.
- Forgetting that wet skin freezes faster. The formula assumes dry skin and no sunshine. Sweat, rain or spray strip heat much faster, so on damp days the real risk is worse than the calculated value. Add a safety margin when you are wet.
- Confusing wind chill with the heat index. Wind chill is the cold-weather feels-like measure. The heat index is its warm-weather counterpart, based on temperature and humidity. They are different formulas for opposite ends of the thermometer and are not interchangeable.
Glossary
- Wind chill
- The feels-like temperature on exposed skin once wind is accounted for, always at or below the true air temperature.
- Feels-like temperature
- A single number combining air temperature and wind (or humidity) to describe how the air feels to a person, rather than to a thermometer.
- NWS 2001 formula
- The wind chill equation adopted by the US National Weather Service and Environment Canada in 2001, based on heat loss from the human face.
- Frostbite
- Freezing of skin and the tissue below it, most common on the nose, ears, cheeks, fingers and toes, and made faster by low wind chill.
- Hypothermia
- A dangerous drop in core body temperature; low wind chill speeds the heat loss that can lead to it.
- Sustained wind
- The steady average wind speed over a period, as opposed to a brief gust, and the value the wind chill formula assumes.
- Heat index
- The warm-weather counterpart to wind chill, combining temperature and humidity to give a feels-like value in hot conditions.
- Exposed skin
- Uncovered skin, usually the face and hands, which is what the wind chill frostbite times apply to.
Frequently asked questions
What is the wind chill formula?
The current US National Weather Service formula, from 2001, is WC = 35.74 + 0.6215T - 35.75V^0.16 + 0.4275T x V^0.16, with temperature in Fahrenheit and wind in miles per hour. A matching metric version uses Celsius and kilometres per hour. This calculator runs both so you get the answer in either unit.
At what wind chill does frostbite happen?
The National Weather Service estimates frostbite on exposed skin in about 30 minutes when the wind chill reaches roughly minus 18 F (minus 28 C), in about 10 minutes near minus 30 F (minus 34 C), and in 5 minutes or less below about minus 50 F. Wet skin freezes faster than these dry-skin figures.
Does wind chill affect the actual temperature?
No. Wind chill only describes how cold it feels on warm skin, because wind carries body heat away faster. The true air temperature, and how cold water, pipes or a car eventually get, is unchanged. Wind just makes objects reach the air temperature more quickly.
Why does even a light wind drop the feels-like temperature so much?
Wind speed enters the formula through the power 0.16, so the first few miles per hour matter most. Going from still air to a light breeze removes the warm layer of air against your skin, which causes a large early drop. Each extra unit of wind after that adds a smaller effect.
Is wind chill the same as the heat index?
No. Wind chill is the cold-weather feels-like measure, based on temperature and wind. The heat index is the warm-weather version, based on temperature and humidity. They use different equations for opposite ends of the thermometer and should not be mixed up.
What temperature range does the wind chill calculator work for?
The NWS wind chill formula is defined for air temperatures at or below 50 F (10 C) and wind above 3 mph (about 4.8 km/h). Outside that range the result is not meaningful, so this tool shows a note when your input falls outside the official range.
Should I use wind speed or gust speed?
Use the sustained wind speed, the steady average, not a one-off gust. The formula assumes continuous exposure to a steady wind, which better reflects the heat loss your skin experiences over several minutes outdoors.
Can wind chill be higher than the air temperature?
Within the valid range, no. Wind can only make you lose heat faster, so the feels-like value is at or below the true temperature. In near-calm air (3 mph or less) the concept does not apply, which is one reason the formula has a lower wind limit.
Does the sun change the wind chill?
The formula assumes no direct sunshine. Bright sun can make it feel several degrees warmer than the calculated wind chill, while shade and moisture make it feel colder. Treat the number as a clear-sky, dry-skin baseline and adjust for conditions.
How do I stay safe when the wind chill is very low?
Cover all exposed skin, especially the face, ears and hands, keep dry, layer clothing, limit time outside and watch for numbness or pale skin. If the wind chill note here shows a high or severe risk, keep outdoor time short and follow official cold-weather warnings.
Sources
- Wind Chill Chart and Frostbite Guide , US National Weather Service (NOAA) (2024)
- The New Wind Chill Equivalent Temperature Chart , Bulletin of the American Meteorological Society (2005)