# Wind Chill Calculator

Wind chill temperature is the temperature felt by the skin rather than the actual temperature due to the wind. The human body loses heat via convection, evaporation, conduction, and radiation. In cold air, wind around the body will increase the rate of heat loss. Therefore the body will feel the temperature to be lower than the actual temperature. This calculator suggests the actual temperature felt by the body by considering the factors of actual temperature and wind speed. On the opposite, the high humidity level will reduce the evaporation rate of sweat in the summer. Therefore the body will feel a higher temperature than the actual temperature. Use the heat index calculator to evaluate the summer temperature.

 Wind Speed mph km/h m/s knots Air Temperature fahrenheit celsius kelvin

RelatedHeat Index Calculator | Dew Point Calculator

The formula to estimate the Wind Chill Temperature Index was provided by the National Weather Service. We give out results for both.

### New Wind Chill Index (After Nov. 2001)

Wind Chill Temperature = 35.74 + 0.6215×T - 35.75×V0.16 + 0.4275×T×V0.16

where T is the actual air temperature in fahrenheit, V is the wind speed in mph.

### Old Wind Chill Index (Before Nov. 2001)

Wind Chill Temperature = 0.081×(3.71×V1/2 + 5.81 - 0.25×V) × (T - 91.4) + 91.4

where T is the actual air temperature in fahrenheit, V is the wind speed in mph.

It can feel great to go outside on a cold day if there's not too much wind, and the sun is shining. Heat from the sun warms you, and you don't really notice the cold air around you very much. On the other hand, even on a day that's not really cold, a sharp wind will make it seem much colder and more unpleasant. The effect of the wind is called the wind-chill factor. You feel like it's a lot colder out there than it really is, because of the effect of wind on your skin.

The scientific explanation isn't very complicated. A solid surface loses heat through evaporation, conduction, and radiation. In this case, it's conduction we're concerned with, which is the actual movement of heat from warm to cold. The rate of conduction depends on the difference in temperature between the surface and its surroundings. As conduction from a warm surface heats the air around it, an insulating boundary layer of warm air forms against the surface. Moving air disrupts this boundary layer, or epiclimate, allowing for cooler air to replace the warm air against the surface. The faster the wind speed, the more readily the surface cools.

The effect of wind chill is to increase the rate of heat loss and reduce any warmer objects to the ambient temperature more quickly. It cannot, however, reduce the temperature of these objects below the ambient temperature, no matter how great the wind velocity. For most biological organisms, the physiological response is to generate more heat in order to maintain a surface temperature in an acceptable range. The attempt to maintain a given surface temperature in an environment of faster heat loss results in both the perception of lower temperatures and an actual greater heat loss. In other words, the air 'feels' colder than it is because of the chilling effect of the wind on the skin. In extreme conditions this will increase the risk of adverse effects such as frostbite.