Wind chill describes how cold it actually feels on your skin when the wind is blowing. The National Weather Service uses a wind chill formula that combines air temperature and wind speed to calculate the rate of heat loss from exposed skin. This free calculator gives you the wind chill index, frostbite risk time, and safety recommendations so you can prepare properly before heading outdoors in cold, windy conditions.
Weather Conditions
Valid for temperatures ≤ 50°F (10°C) and wind ≥ 3 mph (4.8 km/h)
Wind Chill Reference Chart
Wind chill values in °F — color indicates frostbite risk
How to Use the Wind Chill Calculator
Cold air alone is uncomfortable, but add wind and the danger increases dramatically. Wind chill measures the combined effect of temperature and wind on the human body, telling you how cold it truly feels on exposed skin. Whether you are planning a winter hike, commuting to work, or checking conditions before letting kids play outside, knowing the wind chill helps you dress properly and avoid dangerous cold-weather injuries like frostbite and hypothermia.
Step 1: Enter the Air Temperature
Type the current outdoor air temperature into the first field. You can toggle between Fahrenheit and Celsius by clicking the unit buttons. The wind chill formula is valid for temperatures at or below 50 degrees F (10 degrees C). If the temperature is above this threshold, wind chill is not a significant factor and the calculator will let you know.
Step 2: Enter the Wind Speed
Enter the sustained wind speed in either miles per hour or kilometers per hour. You can find current wind speed from your local weather station, a weather app, or a handheld anemometer. The wind chill index requires wind speed of at least 3 mph (4.8 km/h) to produce meaningful results. Light breezes below that threshold do not significantly increase heat loss.
Step 3: Review Your Results
After clicking "Calculate Wind Chill," you will see the wind chill temperature displayed prominently alongside a color-coded frostbite risk indicator. Green means low risk, yellow indicates frostbite is possible within 30 minutes, orange warns of a 10-minute window, and red signals extreme danger with frostbite possible in 5 minutes or less. The comparison section shows the difference between the actual temperature and the feels-like temperature.
Step 4: Check Safety Recommendations
The calculator provides tailored safety tips based on the wind chill severity. These include clothing recommendations, exposure time limits, and warning signs of frostbite and hypothermia. For extreme cold, the advice includes covering all exposed skin, limiting outdoor time, and traveling with emergency supplies.
Understanding the Reference Chart
The wind chill chart below the calculator shows wind chill values for common temperature and wind speed combinations. Cells are color-coded by frostbite risk, making it easy to see how quickly conditions become dangerous as wind speed increases. This chart follows the same data published by the National Weather Service and Environment Canada.
FAQ
Is this wind chill calculator free?
Yes, the wind chill calculator is completely free with no limits or signup required. All calculations run locally in your browser, so nothing is sent to any server.
Is my data safe and private?
Absolutely. Everything runs locally in your browser using JavaScript. No temperature readings, location data, or personal information is stored, transmitted, or shared.
What formula does this wind chill calculator use?
This calculator uses the official NWS/Environment Canada wind chill formula adopted in 2001. For Fahrenheit: Wind Chill = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16), where T is air temperature in degrees F and V is wind speed in mph.
When is the wind chill formula valid?
The NWS wind chill formula is valid when the air temperature is at or below 50 degrees F (10 degrees C) and wind speed is at least 3 mph (4.8 km/h). Outside these conditions, wind chill is not meaningfully different from the actual air temperature.
How quickly can frostbite occur in extreme wind chill?
At wind chills below -25 degrees F (-32 degrees C), frostbite can occur on exposed skin in as little as 5 minutes. Between -10 and -25 degrees F, frostbite risk is within 10 minutes. Between 0 and -10 degrees F, exposed skin may develop frostbite in about 30 minutes.
What is the difference between wind chill and actual temperature?
Wind chill is the 'feels like' temperature that accounts for heat loss from exposed skin caused by wind. While the actual air temperature stays the same regardless of wind, your body loses heat faster in windy conditions, making it feel colder than the thermometer reads.
Can wind chill affect my car or pipes?
No. Wind chill only applies to living organisms that generate body heat. Objects like cars and water pipes will only cool to the actual air temperature, not the wind chill temperature. However, wind does speed up the rate at which objects reach the ambient temperature.
Does humidity affect wind chill?
The current NWS wind chill formula does not factor in humidity. However, wet or damp conditions can increase heat loss from your body beyond what the wind chill index predicts. Wet skin and clothing lose heat much faster than dry, so dress in moisture-wicking layers in cold weather.