Weather 101 is a series of articles where News10’s meteorologists answer your weather questions.
Cecil Willie wanted to know more about the wind chill factor, how we calculate it, and what it means.
Wind chill is a measure of how quickly the body loses heat, and a way to illustrate how the combination of cold air and wind can be especially dangerous.
On a cold day, the air around is has a much lower temperature than our bodies. Heat naturally radiates away from our skin. If there is no wind, that process produces a thin layer of warmer air surrounding us, acting as a buffer and helping us stay warm.
But if there is wind, that layer of warmer air is stripped away and replaced by the colder, surrounding air and your body begins to lose heat much faster. This process is amplifies if winds are especially strong.
Using a formula developed by American, Canadian, and British scientists in the early 2000’s, we calculate a “wind chill index” to give an idea of how the body would react to different combinations of cold and wind.
The formula looks intimidating, but there are numerous conversion charts available to quickly get results. The one below was developed by the National Weather Service.
Let’s use an example to show what the wind chill actually means. If the temperature outside is zero degrees with no wind, your body would eventually loose heat and frostbite would be possible on exposed skin… but it would take a while.
If the temperature were zero with 60 mile per hour winds, the wind chill is -33. Your body would be losing heat at the same rate as if the temperature were -33 and frostbite would be possible within 10 minutes. The actual air temperature is the same in both scenarios, but the effects on your body are very different.
You should also be aware that warmer clothes and/or wearing more layers make it harder for the wind to strip away the warm layer around you. Always important to bundle up!
Kurt Gardinier wanted to know: if air temperature is 34 but the wind chill is 30, would water freeze?
It’s important to note that, while we express Wind Chill in degrees, it is technically not a temperature in and of itself. Rather, it is a way to understand the rate of heat loss.
In Kurt’s example (Wind Chill 30°, Air Temp 34°), the water would cool down faster than normal, at the same rate as if the temperature outside were 30. But once it hit the 34 degree mark (the actual outside temperature) it would stop falling. The water cannot freeze unless its surroundings are also below freezing.
Thanks to Cecil and Kurt for their questions! If you’ve got a weather question you want answered in Weather 101, shoot us an email! You can reach me at firstname.lastname@example.org