How to use the wind chill calculator
- 1 Enter the air temperature and choose °F or °C.
- 2 Enter the wind speed and its unit.
- 3 Read the wind chill in °F and °C.
- 4 Check the frostbite risk before going out.
Worked example
An air temperature of 20 °F with a 15 mph wind. WC = 35.74 + 0.6215 × 20 − 35.75 × 15^0.16 + 0.4275 × 20 × 15^0.16 = 6.2 °F (−14.3 °C): it feels 13.8 °F colder than the air. Cover exposed skin.
Staying safe in the cold
- Dress in layers with a windproof shell.
- Cover your face, ears and hands.
- Watch for numb, pale skin: early frostbite.
- Limit time outside when wind chill is below −18 °F.
Convert temperatures with the Temperature Converter and Celsius to Fahrenheit, and wind speeds with the Speed Converter. For electronics in the cold, read resistor values with the Resistor Color Code Calculator; indoors, size heating and cooling with the BTU Calculator.
How it works: Temperatures are converted to Fahrenheit and wind speeds to miles per hour, the units of the official formula. If the air is warmer than 50 °F or the wind is under 3 mph, wind chill is not defined, so the air temperature is shown instead.
Features
NWS formula
The 2001 US and Canadian wind chill index.
Any units
°F or °C; mph, km/h, m/s or knots.
Frostbite risk
Time to frostbite from the NWS chart.
When to use it
Winter outdoor plans
Dress for the feels-like temperature, not just the thermometer. Convert temperatures with the Temperature Converter.
Running and cycling
Moving into the wind adds to wind chill. Work out your speed with the Speed Calculator.
Outdoor work
Plan breaks to warm up.
Unit conversion
Convert wind speeds with the Speed Converter.
Related Science tasks
Frequently asked questions
What is wind chill?
How cold the air feels on exposed skin when wind carries body heat away faster. It is not the air temperature, and it does not cool objects below the air temperature.
How is wind chill calculated?
With the NWS formula: WC = 35.74 + 0.6215T − 35.75V^0.16 + 0.4275TV^0.16, where T is °F and V is wind speed in mph.
What is the wind chill at 20 °F with a 15 mph wind?
About 6 °F (−14 °C): it feels 14 degrees colder.
When does wind chill apply?
At air temperatures of 50 °F (10 °C) or below and wind speeds of 3 mph or more.
When is there a risk of frostbite?
According to the NWS chart, exposed skin can freeze in about 30 minutes at a wind chill of −18 °F, 10 minutes at −32 °F and 5 minutes at −48 °F.
Can wind chill freeze water or a car radiator?
No. Wind chill affects heat loss from warm bodies. Objects only cool to the actual air temperature, though wind gets them there faster.
What is a wind chill warning?
The National Weather Service issues cold weather advisories and extreme cold warnings when wind chills reach dangerous levels for your area.
What is the opposite of wind chill?
The heat index, which combines heat and humidity to show how hot it feels.
Which wind speed is used?
The wind at about 5 feet, face height. Weather reports give wind at 33 feet, which the formula is adjusted for.
How do I protect myself in high wind chill?
Cover exposed skin, wear layers with a wind-proof outer layer, keep dry, and limit time outside. Watch for numbness and pale or gray skin.
What is the wind chill at 0 °F and 20 mph?
About −22 °F, cold enough for frostbite in about 30 minutes.
Does wind chill matter for pets?
Yes. Animals lose heat faster in wind too; bring pets inside in dangerous wind chills.
Built and reviewed by Hamza Farooq, founder and lead developer
· Last updated
· How we check our tools
· Report a problem