Wind Chill Calculator

Calculate how temperature feels given wind speed or humidity — in °C or °F.

Temperature (°C)

Wind speed (km/h)

Actual temperature

5.0 °C

Feels like

0.1 °C

-4.9 °C

Conditions

Cool — light jacket recommended.

How wind chill and heat index are calculated

Wind chill uses the NWS/Environment Canada formula valid for temperatures at or below 10°C (50°F) and wind speeds above 4.8 km/h (3 mph). It accounts for the rate at which exposed skin loses heat to moving air. Heat index uses the Rothfusz regression formula valid for temperatures above 27°C (80°F) and relative humidity above 40% — it models how humidity reduces the body's ability to cool itself through sweating.

For unit conversion, try Celsius to Fahrenheit or Temperature Converter.

Built and maintained by Meet Shah · Last updated 30 July 2026

What this tool is used for

Working out how cold it will feel given the wind.
Getting a heat index from temperature and humidity.
Deciding what to wear for an outdoor activity.
Comparing two days that share the same temperature.
Checking a forecast's feels-like figure.

Frequently Asked Questions

Which wind-chill formula is used?: The 2001 North American standard: 13.12 + 0.6215T − 11.37V^0.16 + 0.3965T·V^0.16, with T in °C and V the wind speed in km/h at 10 metres. It replaced the 1945 formula, which came from measuring how fast water froze in a plastic cylinder and overstated the effect badly.
When is wind chill valid?: At or below 10 °C and above about 4.8 km/h of wind. Outside that range the formula is not defined — which is why it produces nonsense for a warm breezy day, and why heat index takes over above roughly 27 °C.
Does wind chill affect objects too?: No, and this is the most useful thing to know about it. Wind cannot cool anything below the actual air temperature; it only speeds up the loss of heat that a warm body is already producing. Your car will not freeze at −20 wind chill if the air is at −2.
Why does it matter for frostbite?: Because it estimates how quickly exposed skin loses heat. At −27 °C wind chill, exposed skin can freeze in about 30 minutes; at −40 it is 10 minutes or less. That timing, not the number itself, is what the index exists to communicate.
What is heat index measuring instead?: The opposite failure. In heat, the body cools by evaporating sweat, and high humidity stops that working — so heat index combines temperature with humidity to say how hot it effectively feels. Both indices describe how well your body can shed or hold heat.

Common errors and gotchas

Applying the wind chill formula above its valid temperature range, where it is not defined.
Confusing wind chill with heat index, which apply at opposite ends of the scale.
Assuming wind chill affects objects, when it describes heat loss from exposed skin.
Using a wind speed measured at a different height from the formula's assumption.
Reading the figure as an actual temperature rather than an equivalent sensation.