Wind Chill Calculator
How cold the wind makes it feel — and how quickly exposed skin freezes.
Wind strips away the thin layer of warm air your body holds against its skin, so heat leaves faster and you feel colder than the thermometer says.
How the wind chill calculator works
Wind strips away the thin layer of warm air your body holds against its skin, so heat leaves faster and you feel colder than the thermometer says. Wind chill is the temperature that would produce the same rate of heat loss in calm air.
The formula is the joint 2001 North American standard, developed by Environment Canada and the US National Weather Service from trials on human volunteers in a chilled wind tunnel — it replaced a 1945 version based on how fast water froze in a plastic cylinder, which overstated the effect considerably.
It applies at or below 10 °C with winds above 4.8 km/h. Note that wind chill affects exposed skin only: it does not cool objects below the actual air temperature, so pipes freeze at the real temperature, not the wind chill.
Formula: WCI = 13.12 + 0.6215T − 11.37V^0.16 + 0.3965·T·V^0.16 (T in °C, V in km/h)
Worked examples
| Inputs | Feels like | Note |
|---|---|---|
| −5 °C with a 20 km/h wind | -11.6 °C | feels like −11.6 °C |
| 20 °F with a 15 mph wind | 6.2 °F | feels like about 6 °F |
| Cold but still | -5.0 °C | no wind chill below 4.8 km/h |
FAQFrequently asked questions
What is wind chill?
The temperature that would cause the same rate of heat loss from exposed skin in calm air as the actual temperature and wind do together.
Does wind chill affect my pipes?
No. Wind speeds up cooling but cannot take anything below the actual air temperature. Pipes freeze at the real temperature.
Why does wind make it feel colder?
It strips away the thin layer of body-warmed air against your skin, so heat leaves faster.
When does wind chill apply?
At or below 10 °C with winds above 4.8 km/h. Outside that range the formula is not defined.
How quickly can frostbite happen?
At a wind chill of −40 °C, exposed skin can freeze in 5 to 10 minutes; below −55 °C, in under two minutes.
Where these figures come from
- UK DESNZ / DEFRA — Greenhouse gas reporting: conversion factors — the flight, fuel and waste emission factors used here
- Scarborough et al. (2014), Climatic Change — Dietary greenhouse gas emissions — the per-diet daily emission figures
- US EPA — Technical Assistance Document for the Reporting of Daily Air Quality (AQI) — the PM2.5 breakpoints the air quality calculator uses
- UK Department for Energy Security and Net Zero — conversion factors — the official UK emission factors
Last checked: September 2026. Factors are taken from published government and peer-reviewed sources, each named on the page with its year.