Wind Chill Calculator
Wind Chill Calculator works out Wind chill temperature and Wind chill (degF) from Units, Air temperature and Wind speed. The default figures on this page give wind chill temperature of -17.4; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
4 steps
- V^0.16 = 25^0.16 = 1.6736722
- Twc = 35.74 + 0.6215(5) - 35.75(1.6736722) + 0.4275(5)(1.6736722)
- Twc = -17.4088 degF = -27.4493 degC
- The air feels 22.41 degF colder than the 5 degF air temperature.
Its 4 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
3 sources
What the Wind Chill Calculator calculates
Computes the 2001 North American wind chill temperature from air temperature and wind speed, in Fahrenheit/mph or Celsius/km-h, with the applicability limits the weather services attach to it.
How to use this Wind Chill Calculator
Enter Units, Air temperature and Wind speed. Wind chill temperature updates as you type, and “Use a worked example” loads checked figures you can adjust. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Wind chill temperature, Wind chill (degF) and Wind chill (degC).
The method follows US National Weather Service, "Wind Chill" calculation sheet (NWS El Paso wxcalc), US National Weather Service, NWS Wind Chill Chart and Environment and Climate Change Canada, Wind Chill Index (2001 joint Canada/US index).
NWS chart: 5 degF with a 25 mph wind example
With Units: imperial, Air temperature: 5, Wind speed: 25, the calculator returns Wind chill, reported as the weather service rounds it: -17. This example is checked against an independent source in the test suite.
What you can compare
Change one input at a time to see how it affects Wind chill temperature, Wind chill (degF) and Wind chill (degC). The inputs you can vary are Units, Air temperature and Wind speed.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
At what temperature does wind chill start?
Computes the 2001 North American wind chill temperature from air temperature and wind speed, in Fahrenheit/mph or Celsius/km-h, with the applicability limits the weather services attach to it. On the figures this page opens with — air temperature 5 and wind speed 25 — the wind chill temperature is -17.4. Put your own figures in their place and the working updates beside the result.
How to estimate wind chill factor?
Computes the 2001 North American wind chill temperature from air temperature and wind speed, in Fahrenheit/mph or Celsius/km-h, with the applicability limits the weather services attach to it. Open “How this is worked out” beside the result to see each step for your own figures.
What is an unsafe wind chill?
Computes the 2001 North American wind chill temperature from air temperature and wind speed, in Fahrenheit/mph or Celsius/km-h, with the applicability limits the weather services attach to it. On this page it is computed from Units, Air temperature and Wind speed and shown as Wind chill temperature, Wind chill (degF) and Wind chill (degC).
How long is it safe to be outside with wind chill?
On the figures this page opens with — air temperature 5 and wind speed 25 — the wind chill temperature is -17.4. No single number fits everyone: change any figure above and the answer updates as you type, with each step of the arithmetic beside it.
What information do I need for the Wind Chill Calculator?
You need Units, Air temperature and Wind speed. The page opens with default figures that give wind chill temperature of -17.4, so you can see the scale before entering your own.
What does this Wind Chill Calculator show?
It shows Wind chill temperature, Wind chill (degF), Wind chill (degC), Wind chill, reported as the weather service rounds it, Degrees colder than the air temperature (degF), Degrees colder than the air temperature (degC), Siple-Passel wind chill index and Within the published applicability range, with the working and any warnings for your entries.