As you step onto your back porch with this view as a backdrop, you shiver! The temperature is 40 degrees (F) but it feels like it's freezing. Why? What can make a 40 (F) degree day seem like it's 28 degrees outside?

A 10 mile-per-hour wind!

In 1939, Paul A. Siple, an Antarctic explorer, first called it 'the wind chill factor'. This is when the air motion (wind) around us can cause us to loose some of our body heat.

What makes this situation dangerous is that when we hear that the temperature is 40 degrees outside, we might not dress warm enough to equal the wind that's rushing around us.

So, the next time you hear your local temperature, find out what the wind chill factor is. It might make the difference between a sweater or a coat.

Below you'll find a chart that shows you just how much difference a cold wind can make, even on a sunny day.

For another example: a 20 mile per hour (mph) wind can turn a 50° day seem like it's 36°. That's almost freezing! Brr!

                                                  TEMPERATURES IN FAHRENHEIT

                        WIND SPEED         50°              40°              30°

                             5mph                 48°               37°               27°
                 
                            10mph                 40°               28°               16°

                            20mph                 36°               22°               9°