Wednesday, November 27, 2013

Don't Tell Me What it Feels Like

I can tell that winter has returned, because now instead of giving the real temperature on TV, they start telling us what it "Feels Like".  And "feels like" is actually just an easy to understand replacement phrase for "Wind chill factor".

According to Wikipedia,

"Wind chill (popularly wind chill factor) is the perceived decrease in air temperature felt by the body on exposed skin due to the flow of cold air."

Scientists have worked out the wind chill factor temperature for each degree of real temperature, and at each increase of wind speed.  Wind chill temperature tells you how quickly you will get frostbite if your bare skin is exposed to that wind.  The wind chill calculation is helpful for people who are at risk of frostbite.

But, in my opinion, the wind chill readings are not well understood by ordinary mortals such as meteorologists and weather announcers on TV.  "Wind chill factor of -30c" does not mean "Feels like -30c".

When I was a kid up north walking to school in the middle of winter, my mother used to always tell me the temperature before I left the house.  She would say "It's 30 below zero!!"  as I walked out the door without either hat or gloves.  Thanks to her constant reminders, I have a pretty good idea what it "Feels Like" at all the different temperatures and wind speeds, while walking without a hat or gloves and my ears in the early stages of frostbite.  It is not what the weatherman says it "Feels Like".  A real -35c feels a lot colder than a wind chill factor of -35c.  Why?  If you have a wind chill reading of -35, the "real temperature (i.e. the one showing on the "real" thermometer) is only -19 when the wind is 50 kph.  That means if you can get out of the wind, you will be much warmer (or less cold).  But if the real temperature is -35, you have no place to go, it is -35 everywhere.  If it is only a wind chill of -35, there are lots of ways to get out of the wind.  Walk behind a bigger person, change sides of the street. walk backwards, etc.  Additionally, if the wind happens to be coming from behind, you only need to walk a little faster, and you avoid the wind chill.  And I have not yet even put on my hat and gloves, which happen to be wind proof anyway.

Lately I have noticed a new trend on TV, which is to substitute "Feels like" for the more meaningful term "Wind chill factor".  Don't tell me what it "feels like".  I know what it feels like, or given the real temperature and wind, I can figure it out.  Your job should be to tell me the real temperature, and the wind speed and direction.  Different people have different tolerances to cold.  Different people wear different clothes.  Cold does not feel the same to everybody.

On a motorcycle, the weather presenter's "Feels like" temperature is even less meaningful.  Partly because I have no exposed skin while riding my motorcycle on a cold day.  And partly because, even if there was some exposed skin, it is not exposed to the wind at the normal ground speed they measure.

So unless someone with a perfectly average human body is outside in the nude, standing still on top of a treeless hill, don't tell them what the temperature "feels like"  You don't know what it feels like.  Just give the real temperature, and the wind speed and direction, and let them work it out for themselves.

Picture: from

1 comment:

  1. I concur.

    I've been out in -40° weather. And I've been out in '-40 windchill.' I'd sooner take the -40 windchill any time.