Why Does 40 Degrees in Indiana & Kentucky Feel ‘Cold’ One Day and ‘Warm’ The Next?

Stories about the unpredictability of midwest weather are legendary.  A prime example- January 3rd, 2000.  That's when a major cold front moved through western Kentucky and brought with it a destructive tornado. My hometown, Owensboro, was extremely hard hit. We went from nearly 80 degrees to an F-3 tornado to snow within a period of about 24 hours.  It was crazy. Clearly, that's a rather extreme example of what can happen here with the instability in our temperatures here in the Commonwealth. But the truth is- our weather is all over the place this time of you.

And, speaking of temperatures, have you ever noticed how differently we perceive them? For instance, why is it that 40 degrees can feel warm some days and bone-chillingly cold another day? How is that even possible?  Shouldn't 40 feel like 40 anytime it's 40?

Well, one would think. However, as it turns out, it doesn't necessarily work that way and there are scientific and meteorological reasons why.

The first? As Scientific American explains and we already know, the sun's the sun. It's hot.

It doesn't matter if it's in the summer or the winter. The sun, that flaming big ball of gas, is hot regardless. And it has an effect on everything in its rays.

Earth is covered with water, soil, rocks, snow and ice as well as a wealth of human-made materials, such as concrete. When these surfaces are exposed to the sun, they warm up.

There is no disputing that a 40-degree day can feel a lot warmer if the sun's out. Look. I am a tennis player. If it's really cold outdoors, the chances of me playing outside are basically nil. I'll got play indoors at the racquet club near my house. However, if the sun's out and it's 40, I am probably down for an hour or two on the courts outside. As stated above, the shining sun, even during the winter, is warming up the concrete on the court.

There's another explanation as well and it's related to the amount of humidity in the air. We already know that humidity in Kentucky summers can be just brutal. Sweltering really.  Humidity can take a temperature of 90 degrees and raise the heat index well into triple digits.  Those "feels like" temperatures in this state can roast you like a hog.

Oddly enough, high humidity levels have almost a reverse effect during the winter months. Instead of warming you up, they'll make you feel even colder.

Wait? What?  How is that possible?

Here's a great explanation from Brennan's Heating & Air Conditioning:

If the air is humid, it has a high water content. The process of moisture evaporating off your skin naturally cools you down. Your body won't sweat when it's cold, bu the humidity from the air can place moisture on your skin and give you the same chilly effect.

 

They go on to say this:

If the humidity levels are extremely high, the moisture can saturate your clothing. This leaves chilled water molecules against your skin and makes a cold environment feel even chillier. 

As I mentioned before, I am a tennis player and I will play outside in the winter. Just a few weeks ago, I was playing and sweating- a lot. Because of all that moisture, I started to get really cold (because the sun wasn't really out much that day).  The chill finally won out. I got so cold on court that I told my tennis partner that I needed to go home and get in front of my faux fireplace.  That's exactly what I did.

So, see! We're not crazy. Even though 40's 40 it may not always feel like 40. It's entirely possible for 40 to feel warm one day and cold the very next.