Wind Chill Calculator

Q: Does wind chill affect animals and pets?

Yes. Wind chill applies to people and animals. 1 That includes dogs, cats, and livestock. Pets with short fur or small bodies are especially at risk. If conditions are too cold for you, they are likely too cold for your pets as well. Bring them indoors or provide warm shelter.

Introduction

Wind chill is how cold it actually feels on your skin when the wind is blowing. Even if the thermometer says 30°F, a strong wind can make it feel much colder. This is because wind strips heat away from your body faster than still air does.¹ The stronger the wind, the colder it feels. Our wind chill calculator lets you type in the air temperature and wind speed to find out the "feels like" temperature. This number, called the wind chill index, helps you know how to dress and stay safe when you go outside in cold, windy weather. It uses the formula developed by the National Weather Service to give you an accurate result.

How to Use Our Wind Chill Calculator

Enter the air temperature and wind speed to find out what the temperature actually feels like on your skin.

Air Temperature: Type in the current outdoor temperature. You can use Fahrenheit or Celsius. This is the number you see on a thermometer. The NWS defines wind chill only for temperatures at or below 50°F.¹ That is 10°C.

Wind Speed: Enter how fast the wind is blowing in miles per hour (mph) or kilometers per hour (km/h). You can find this from a local weather report or a handheld wind meter. The NWS defines wind chill only for wind speeds above 3 mph.¹ That is about 5 km/h.

Wind Chill Temperature (Result): After you enter your values, the calculator will show you the wind chill temperature. This is how cold it really feels on exposed skin when the wind is blowing. The stronger the wind and the lower the temperature, the colder it will feel. Use this number to dress properly and stay safe outdoors in cold, windy weather.

Understanding Wind Chill

Wind chill is the temperature your body actually feels when cold air and wind work together to strip heat from your skin. On a calm day, a thin layer of warm air sits close to your body and acts like a blanket. When the wind blows, it tears that warm layer away and replaces it with cold air.³ The faster the wind, the faster you lose heat, and the colder it feels. That is why a 20°F day with a 15 mph breeze can feel like only 6°F on your exposed skin. A related weather metric, the dew point, shows how moisture in the air affects comfort.

How Wind Chill Is Calculated

The National Weather Service (NWS) uses a wind chill formula that was introduced in North America in November 2001.⁴ It takes two inputs, the actual air temperature and the wind speed, and produces a single number: the wind chill temperature. The formula is based on a human face model, and NWS researchers applied it to 12 test subjects.¹ The NWS defines it only for air temperatures at or below 50°F and wind speeds above 3 mph.¹ Outside those limits, no wind chill is given.

Why Wind Chill Matters

Wind chill is not just a number on a weather report. It directly affects your safety. For example, at 0°F with a 15 mph wind, the wind chill is -19°F, and exposed skin can freeze in 30 minutes.¹ Environment and Climate Change Canada gives these steps for wind chill values on the Celsius scale: at -28 to -39, exposed skin can freeze in 10 to 30 minutes; at -40 to -47, in 5 to 10 minutes; at -48 to -54, in 2 to 5 minutes; and at -55 or colder, in less than 2 minutes.³ Hypothermia, a dangerous drop in core body temperature, also becomes a serious risk as wind chill values fall. Be even more cautious with children, older adults, and anyone in poor health.¹

Frostbite Risk Levels

Frostbite occurs when body tissue freezes.² The fingers, toes, ear lobes, and tip of the nose are the most susceptible.² Redness or pain may be the first sign, and other signs include a white or grayish-yellow skin area, skin that feels unusually firm or waxy, and numbness.⁵ The reference chart in the calculator shades each wind chill by how fast exposed skin can freeze.

Heat Loss and the Human Body

Your body constantly produces heat and releases it into the air. The heat loss rate the calculator shows comes from the older Wind Chill Index of Siple and Passel, published in 1945, which described the rate of heat loss of a small cylinder per unit surface area.⁴ Researchers later pointed out flaws in that index, and a new formula replaced it in North America in November 2001.⁴ The heat loss number, in watts per square meter (W/m²), is a rough way to compare how much faster heat is lost as the wind rises.

Practical Tips for Cold, Windy Weather

Dress in several layers of loose-fitting, warm clothing, because the air trapped between the layers insulates you.² A moisture-wicking base layer, an insulating middle layer, and a wind-resistant outer shell work well. Cover every bit of exposed skin, especially your face, ears, and hands. Stay dry, because wet clothing loses its insulating ability and pulls heat from your body far more quickly. Limit your time outside when wind chill values are low, and take regular warm-up breaks indoors. If you notice numbness or skin color changes, get inside right away and warm the affected area gently. Do not rub or massage frostbitten skin.⁵

Formulas used

NWS Wind Chill Temperature Index ¹

WC = 35.74 + 0.6215\,T - 35.75\,V^{0.16} + 0.4275\,T\,V^{0.16}

Heat Loss Rate (Siple–Passel Wind Chill Index, W/m²)

Q = \left(12.1452 + 11.6222\sqrt{v} - 1.16222\,v\right)\times(33 - T_c)

Fahrenheit to Celsius ⁶

T_C = \frac{T_F - 32}{1.8}

Celsius to Fahrenheit ⁶

T_F = T_C \times 1.8 + 32

Frequently asked questions

What is wind chill temperature?

Wind chill temperature is the "feels like" temperature on your skin when the wind is blowing. Wind pulls heat away from your body faster than still air.¹ So even if the thermometer reads 20°F, a 15 mph wind can make it feel like 6°F. The wind chill number tells you how cold it actually feels on exposed skin.

Why does the wind speed need to be above 3 mph?

The NWS defines wind chill only for wind speeds above 3 mph, so the calculator needs a speed above that.¹ The 2001 wind chill model already assumes a person walking into the wind at 1.34 m/s, the average walking speed of American pedestrians, so even still air counts as some air movement.⁴ That walking speed is about 3 mph.

What does the heat loss rate in W/m² mean?

The heat loss rate comes from the older Siple and Passel Wind Chill Index, first published in 1945, which described the rate of heat loss of a small cylinder per unit surface area.⁴ It is shown in watts per square meter (W/m²), and a higher number means heat is lost faster in the wind. A new formula replaced that index for wind chill in North America in November 2001.⁴

Is wind chill the same as the actual air temperature?

No. The actual air temperature is what a thermometer reads. Wind chill is always equal to or lower than the actual temperature. It represents how cold your skin feels because of the wind. Objects like water pipes will not cool below the actual air temperature, whatever the wind chill.¹ They freeze based on the actual air temperature.

Can wind chill make water freeze faster?

Wind chill cannot make the temperature of an object drop below the actual air temperature. However, wind can make an object reach the air temperature faster by removing heat more quickly.¹ So if the air is already below 32°F, wind helps water freeze sooner, but it won't freeze water if the actual air temperature is above 32°F.

What is the difference between wind chill and feels like temperature?

In cold weather, they are the same thing. The "feels like" temperature shown on weather apps in winter is the wind chill value. In warm weather, the "feels like" number uses the heat index instead, which factors in humidity rather than wind.

Does humidity affect wind chill?

The official NWS wind chill formula does not include humidity as a factor. It only uses air temperature and wind speed. NWS researchers found that relative humidity changed the result by less than 1 degree, so it was left out of the formula.¹ However, wet skin gets cold even quicker, because there is more moisture to evaporate.³

What does the Temperature Drop result mean?

The Temperature Drop shows the difference between the actual air temperature and the wind chill temperature. For example, if the air is 20°F and the wind chill is 6°F, the temperature drop is 14°F. This tells you how much colder the wind makes it feel compared to a calm day.

Does wind chill apply indoors?

No. Wind chill only matters outdoors where wind is blowing on your exposed skin. Indoors, with no wind, the temperature you feel is the actual room temperature. If you feel cold indoors from a draft, that is a small-scale version of the wind chill effect, but the NWS formula is designed for outdoor weather conditions.

Does wind chill affect animals and pets?

Yes. Wind chill applies to people and animals.¹ That includes dogs, cats, and livestock. Pets with short fur or small bodies are especially at risk. If conditions are too cold for you, they are likely too cold for your pets as well. Bring them indoors or provide warm shelter.

Sources

Understanding Wind Chill. NOAA National Weather Service. Wind Chill FAQ. Accessed September 29, 2026.

Wind Chill Questions. NOAA National Weather Service. What is Frostbite?; Dress for safety. Accessed September 29, 2026.

Wind chill and the Wind Chill Index. Environment and Climate Change Canada. Your safety risk for wind chill exposure. Accessed September 29, 2026.

Osczevski R, Bluestein M. The New Wind Chill Equivalent Temperature Chart. Bulletin of the American Meteorological Society. 2005;86(10):1453-1458. doi:10.1175/BAMS-86-10-1453. Accessed September 29, 2026.

Preventing Hypothermia. Centers for Disease Control and Prevention. Spot Frostbite; Treat. Accessed September 29, 2026.

NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically. National Institute of Standards and Technology. Special Publication 811, App. B.8 (degree Fahrenheit). Accessed September 29, 2026.

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