Use this wind chill calculator to see how cold it feels on exposed skin from air temperature and wind speed.
Advanced options
How to use our Wind Chill Calculator
- Enter Air temperature, then choose the matching Temperature unit.
- Enter Wind speed, choose the matching Wind speed unit, and use a steady wind speed when you can instead of a short gust.
- Pick Show result in if you want the answer displayed in Fahrenheit or Celsius.
- Click Calculate, then read Wind chill first, followed by Cold safety note, Feels colder by, and Formula use range.
- Sanity-check the result: if Wind chill is almost the same as Air temperature, the wind may be light; if Formula use range says the formula is not defined, use the air temperature as the main reading instead.
Definitions
Air temperature: The real outdoor temperature measured by a thermometer.
Wind chill: A feels-like estimate for exposed skin in cold, windy weather [1].
Wind speed: How fast the air is moving. This calculator uses your chosen unit, then converts it to miles per hour for the official formula.
Formula use range: The official NWS wind chill formula is used only when air temperature is 50 F or lower and wind speed is above 3 mph.
Feels colder by: The signed difference between Wind chill and Air temperature. A negative value means the wind chill is colder than the air temperature.
Cold safety note: A plain-language summary of cold danger based on the computed wind chill band.
Frostbite timing: An approximate time band shown only when the wind chill falls in an official chart range that includes a timing estimate.
Common mistakes and quick fixes
Mistake: Typing a feels-like value into Air temperature instead of the real thermometer reading.
Fix: Enter the actual outdoor reading in Air temperature , then let Wind chill estimate how cold it feels.
Mistake: Choosing the wrong Temperature unit for the number you entered.
Fix: If your temperature number is in Celsius, set Temperature unit to Celsius; if it is in Fahrenheit, set it to Fahrenheit before you calculate.
Mistake: Entering a gust into Wind speed and treating it like the steady wind.
Fix: Use the more typical steady value for Wind speed when possible, then check the Cold safety note for the easier-to-read takeaway.
Mistake: Mixing up Wind speed unit , such as entering km/h while mph is selected.
Fix: Match the number to the correct Wind speed unit so Wind chill and Feels colder by come out right.
Mistake: Expecting the official formula to work when winds are calm or the weather is mild.
Fix: Read Formula use range ; if it says the formula is not defined, use the actual Air temperature as the main condition.
Mistake: Reading Feels colder by as if it should always be positive.
Fix: A negative Feels colder by value is normal here and means it feels colder than the thermometer reading.
Limitations & Key Assumptions / Boundary Conditions
- The official wind chill formula applies only when air temperature is 50 F or lower and wind speed is above 3 mph after unit conversion.
- This is a feels-like estimate for exposed skin, not the actual thermometer reading.
- The safety notes assume outdoor, shaded conditions and do not adjust for bright direct sun.
- The calculator uses steady wind speed when possible; short gusts can make real conditions feel different.
- If conditions are outside the official formula range, the calculator should not be used to create a standard wind chill value.
- Wind chill does not mean water or objects can cool below the actual air temperature just because the number looks lower.
Methodology
How the calculator works
This calculator first converts your entries into the units used by the official National Weather Service formula: degrees Fahrenheit for temperature and miles per hour for wind speed [2]. If the air temperature is above 50 F or the wind speed is 3 mph or less, the calculator does not apply the official wind chill formula and instead explains that the formula is not defined for those conditions [2].
Formula
WCF = 35.74 + 0.6215 x T - 35.75 x (V^0.16) + 0.4275 x T x (V^0.16)
Here, WCF is wind chill in degrees Fahrenheit, T is air temperature in degrees Fahrenheit, and V is wind speed in miles per hour.
WCC = (WCF - 32) x 5 / 9
This second step is used only when the result is displayed in Celsius.
Feels colder by = displayed wind chill - displayed air temperature
A negative difference means the wind makes it feel colder than the thermometer reading.
Safety interpretation
After computing wind chill, the calculator maps that value to a simple Cold safety note. When the result falls into an official frostbite timing band, it also shows Frostbite timing as a plain-language estimate such as about 30 minutes, about 10 minutes, or about 5 minutes [2]. If the result does not fall into one of those timing bands, the calculator leaves the timing estimate off instead of guessing.
Mini example
Suppose Air temperature is 0 F and Wind speed is 15 mph. Those values are inside the official use range, so the formula is applied.
WCF = 35.74 + 0.6215 x 0 - 35.75 x (15^0.16) + 0.4275 x 0 x (15^0.16)
WCF about -19 F
So Wind chill is about -19 F. The signed difference is -19 - 0 = -19 F, so Feels colder by is -19 F.
Practical notes
The result is meant for people outdoors with exposed skin, not indoor spaces or heated clothing systems. Real conditions can feel different because of sunlight, clothing, moisture, terrain, or using gusts instead of a steady wind [2].