Quick answer
The wind chill index is WC = 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T·V^0.16 (T in °F, V in mph). At 20 °F with a 15 mph wind the wind chill is 6.2 °F.
Enter the air temperature in °F and the wind speed in mph. The calculator returns the wind chill.
Related tools: Dew Point Calculator: Dew point from temperature and relative humidity. Heat Index Calculator: Apparent temperature from air temperature and relative humidity (°F). Wind Power Estimate Calculator: Power from a wind turbine rotor at a wind speed.
How to use the Wind Chill Calculator
- Enter air temperature (°F) (between -60 and 50).
- Enter wind speed (mph) (between 3 and 150).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Air temperature | A number, in °F | ≥ -60, ≤ 50 |
| Wind speed | A number, in mph | ≥ 3, ≤ 150 |
Formula and method
Formula
WC = 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T·V^0.16
IEEE-754 double precision; shown to at most 6 decimal places.
NWS 2001 wind chill index, valid for T ≤ 50 °F and wind speed ≥ 3 mph.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Air temperature = 20; Wind speed = 15.
| Result | Value |
|---|---|
| Wind chill | 6.2 °F |
Example 2
Inputs: Air temperature = 0; Wind speed = 10.
| Result | Value |
|---|---|
| Wind chill | -15.9 °F |
The first line is the headline result (wind chill). IEEE-754 double precision; shown to at most 6 decimal places.
What it describes
Wind chill is how cold exposed skin feels, not the actual air temperature. At −20 °F wind chills, frostbite can occur on exposed skin in 30 minutes or less.
Valid range
The formula is valid only for temperatures at or below 50 °F and wind speeds of 3 mph or more. It does not include sun or humidity. Objects such as pipes cool only to the air temperature, not to the wind chill.
How the result changes with air temperature
Holding every other input at the first worked example, this table changes only air temperature. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Air temperature | Wind chill |
|---|---|
| 10 | -6.6 °F |
| 20 | 6.2 °F |
| 40 | 31.8 °F |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Air temperature: entering "60" shows "Air temperature must be at most 50." beside that field and no result.
- Wind speed: entering "1" shows "Wind speed must be at least 3." beside that field and no result.
Choosing between the Wind Chill Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Dew Point Calculator](/science/dew-point/) | air temperature and relative humidity | Dew point |
| [Heat Index Calculator](/science/heat-index/) | air temperature and relative humidity | Heat index |
| [Wind Power Estimate Calculator](/science/wind-power-estimate-calculator/) | rotor diameter, wind speed and power coefficient | Power |
| [Acceleration Calculator](/science/acceleration-calculator/) | initial velocity, final velocity and time | Acceleration |
| [Mole Calculator](/science/mole/) | start from and molar mass | Amount |
Background: environment and acoustics
Decibels are a logarithmic scale, so sound levels cannot be added arithmetically: two equal sources raise the level by about 3 dB, not double it. Environmental and emissions results depend on the factors behind them (for example the US EPA's equivalency factors), which are averages for a country, fuel and year.
Use the result to compare scenarios rather than as a measured value.
Assumptions and limitations
- Valid only for T ≤ 50 °F and V ≥ 3 mph
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for air temperature and wind speed to confirm this.
Frequently asked questions
Can wind chill freeze water?
No, only down to the air temperature.
What is a dangerous wind chill?
Wind chills below about −20 °F can cause frostbite on exposed skin in 30 minutes or less.
Does it apply in summer?
No. The formula is valid only at or below 50 °F; in warm weather the heat index applies instead.
What does the Wind Chill Calculator calculate?
Wind chill temperature (°F, mph). It returns Wind chill.
What formula does the Wind Chill Calculator use?
WC = 35.74 + 0.6215T − 35.75V^0.16 + 0.4275T·V^0.16. NWS 2001 wind chill index, valid for T ≤ 50 °F and wind speed ≥ 3 mph.
What do I need to enter in the wind Chill Calculator?
You enter Air temperature (°F) and Wind speed (mph).
How is the result rounded or limited?
IEEE-754 double precision; shown to at most 6 decimal places. Valid only for T ≤ 50 °F and V ≥ 3 mph.
What is an example of a wind Chill result?
With air temperature 20 and wind speed 15, the wind chill is 6.2 °F.
Where does the method come from?
The method follows: Osczevski R, Bluestein M, Bull Am Meteorol Soc 2005;86:1453–1458; NWS Wind Chill Temperature Index.
Related calculators
- Dew Point Calculator — Dew point from temperature and relative humidity.
- Heat Index Calculator — Apparent temperature from air temperature and relative humidity (°F).
- Wind Power Estimate Calculator — Power from a wind turbine rotor at a wind speed.
- Acceleration Calculator — Average acceleration from change in velocity over time.
- Mole Calculator — Convert between mass, moles and number of particles.
- Density Calculator — Solve mass, density or volume.
Sources
- Osczevski R, Bluestein M, Bull Am Meteorol Soc 2005;86:1453–1458
- NWS Wind Chill Temperature Index
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.