Transparent method
The formula
Worked example
Example inputs
How to interpret the result
The wind chill formula is only meteorologically valid within its documented range, roughly 50°F and below with wind at or above 3 mph, so applying it outside those conditions produces a number the National Weather Service itself doesn't consider meaningful, even though the calculation will still run and return a result.
Before you rely on it
What to check
Confirm the input temperature and wind speed actually fall within the formula's documented valid range before treating the output as a meaningful feels-like figure.
The common error
Where people go wrong with wind chill calculator
Applying the wind chill formula at a mild temperature or in calm wind and treating the output as meaningful. Outside its documented valid range, the National Weather Service itself doesn't consider the result meteorologically valid.
Sensitivity evidence
How air temperature (°f) changes the feels-like temperature (°f)
| Air temperature (°F) | Feels-like temperature (°F) | Difference from actual temperature |
|---|---|---|
| 16 | 1.1 | -14.9 |
| 18 | 3.7 | -14.3 |
| 20worked example | 6.2 | -13.8 |
| 22 | 8.8 | -13.2 |
| 24 | 11.3 | -12.7 |
Every input, tested
Which input moves the feels-like temperature (°f) most
| Input | Tested from | To | Feels-like temperature (°F) at each end | Swing |
|---|---|---|---|---|
| Air temperature (°F) | 18 | 22 | 3.7 to 8.8 | 5.1 (82%) |
| Wind speed (mph) | 14 | 17 | 6.7 to 5.4 | 1.3 (21%) |
Two variables at once
Feels-like temperature (°F) by air temperature (°f) and wind speed (mph)
| Air temperature (°F) \ Wind speed (mph) | 12 | 15 | 18 |
|---|---|---|---|
| 16 | 2.7 | 1.1 | -0.224 |
| 18 | 5.2 | 3.7 | 2.4 |
| 20 | 7.7 | 6.2 | 5 |
| 22 | 10.2 | 8.8 | 7.6 |
| 24 | 12.7 | 11.3 | 10.2 |
Step by step
The worked example, input by input
| Input | Value used |
|---|---|
| Air temperature (°F) | 20 |
| Wind speed (mph) | 15 |
| Feels-like temperature (°F) | 6.2 |
| Difference from actual temperature | -13.8 |
Where the inputs come from
Enter the air temperature in degrees Fahrenheit and the wind speed in miles per hour. The National Weather Service formula applies for temperatures at or below 50 degrees and wind speeds above 3 miles per hour, and gives the feels-like temperature on exposed skin. Use the wind speed measured at about 5 feet above ground, not the higher values reported at airports at 33 feet, or adjust the value.
When the result stops applying
Wind chill applies only to exposed skin and does not lower the actual temperature, so pipes, cars and objects freeze at the real air temperature, not the wind chill. It assumes shade and no sun, and the formula was designed for a person walking. Dry cold and wet cold feel different. Individual tolerance varies.
What to compare it with
See the heat version on the heat index calculator, humidity effects on the dew point page, and heating demand on the degree days calculator. The temperature and speed converters change units, and the snow-to-liquid calculator relates to winter storms.
People also ask
Frequently asked questions
Does wind chill affect objects like car engines and pipes?
No. Wind can cool a warm object faster toward the air temperature but cannot cool it below the actual air temperature.
When does wind chill become dangerous?
Values around minus 20 Fahrenheit can cause frostbite on exposed skin in about 30 minutes, and lower values act faster.
Does wind chill apply above 50 degrees?
No. The formula is defined for temperatures at or below 50 degrees Fahrenheit and winds above 3 miles per hour.