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Thursday, February 11, 2016

Wind Chill - It can be a very big deal!



Each year when the temperatures drop precipitously, I receive several inquiries from readers who tell me that they are confused with the difference between the actual temperature and the "Wind Chill."  

One neighbor stated "What's the big deal? The actual air temperature is what it is no matter what it may feel like, isn't it?"

"Wind Chill" or, as it is sometimes referred to, "feels like" temperature, is the perceived decrease in air temperature felt by the body on exposed skin due to heat loss caused by the flow of air.

The human body has a core temperature of roughly 98.6F.  When the air surrounding us is still (no wind) our bodies slowly lose heat via convection and the body can easily deal with such minimal heat loss.

However, when winds blow across the exposed surface of skin we lose heat more rapidly via conduction as the wind draws heat away from our body.  




Thus, if your skin is exposed to the wind, your body cools more quickly than it would have on a still day.  The stronger the wind, the faster the cooling.  The lower the temperature, the more impact the wind has.  If your skin is wet, there will be additional cooling due to the evaporation of moisture.  Rapid cooling due to wind will cause your body to sense or "feel" that it is colder than the actual ambient air temperature and your body starts to work harder to maintain your core body temperature.

If your body starts to lose heat faster that it can generate it, hypothermia and frostbite become real concerns so yes, "Wind Chill" can be a very big deal and it's worth keeping an eye on wind chill values even if the notion of your skin "feeling like" a certain temperature may be a bit confusing.

The National Weather will issue a Wind Chill Advisory or Warning as necessary....

A Wind Chill Advisory will be issued by the National Weather Service when the wind chill is low enough that it poses a threat to human health and life if adequate protection is not taken against hypothermia and frostbite.

Wind Chill Warning will be issued by the National Weather Service when the wind chill is low enough that it actually becomes life threatening.

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