ROCHESTER, NY (WROC) – Cold feels colder when it comes to wind chill, and this value is extremely important when it comes to describing how cold it actually feels. There are many important processes happening that bring the “feels like” temperature lower than the actual temperature.

The first key is wind. Without wind, there is no wind chill. The second key is exposed skin. Imagine your skin as a radiator of heat. When you wear a long sleeve shirt for example, the warmth radiating off your forearm bounces off the shirt and back onto your skin. That will keep you warmer. The thicker the layer, the warmer your arm can stay. Without that layer, the radiating warmth simply leaves your skin.

As the warmth leaves your skin, you will start to feel colder. Wind chill is calculated as temperatures are below 39°, so as temperatures drop, the warmth will radiate off you even faster. Now we can add wind. That wind will move across exposed skin and sweep away any of the warmth that was slowly radiating away and the process will be accelerated. That is why it feels much colder than the actual air temperature.

The equation for wind chill can be seen in the chart above. It is based on wind speed at an average height of five feet (or around 2 meters) as well as heat transfer theory. Note that as the temperatures drop, a small increase in wind speed can result in a rapidly colder wind chill, while temperatures above 20° do not see a significant wind chill even with stronger winds.