Explaining Wind Chill

When temperatures really start to tumble in the winter, you will often hear us refer to the wind chill. Many times when we bring up "what the air feels like," we get a lot of questions about what that really means. Frequently people will tell us they think we are making it up or that it's some kind of scare tactic to make cold air sound colder. It's not. Wind chill is a real thing that was developed to help us all better understand how cold air and wind is more harmful to your body than that just that same level of cold.

According to the National Weather Service who developed this chart and the equation for wind chill, "Wind chill is based on the rate of heat loss from exposed skin caused by wind and cold. As the wind increases, it draws heat from the body, driving down skin temperature and eventually the internal body temperature. Therefore, the wind makes it FEEL much colder." It's important to note that wind chill should only be considered for people and animals. When the wind is strong during cold weather, it will cool your pipes and your car faster. But the wind chill is meant to demonstrate what the wind and cold will feel like on skin, not to inanimate objects.

Let's use today as an example:

At their highest, temperatures climbed into the upper 30s for most of you Saturday afternoon. That's the number you will read on the thermometer outside on your back patio. We also had wind gusts over 30 mph, and the wind blew consistently 10-20 mph most of the afternoon.

That made the air feel like the upper 20s and low 30s at the warmest part of the day.

The air was also incredibly dry Saturday. While that doesn't factor into determining the wind chill value, it certainly affects how the air feels to your body. This is the reason you found yourself reaching for the lip balm more often or noticed your hands were starting to crack.

Still not convinced? Here's more info from the National Weather Service about how their calculator computes the wind chill when given the temperature and wind speed:

From the user, we are given an air temperature (T) and a wind speed (Windsfc).
In order to calculate the Wind Chill, the temperature must be converted to degrees Fahrenheit (°F). Also, in order to calculate the Wind Chill, the wind speed must be converted to miles per hour (mph).
Then, the Wind Chill can be calculated using this formula:
WindChill = 35.74 + (0.6215 × T) − (35.75 × Windsfc^0.16 ) + (0.4275 × T × Windsfc^0.16 )