The “Dog Days” of summer are here, and in no time, the mercury can go from a comfortable 60° to a scorching 95°.  Adding to the misery most of the time is the humidity.   With a relative humidity of 50% when the temperature is 95°, it actually feels more like 105° outside.  Whew…

The hottest days of summer in Wisconsin often involve higher humidity levels, making the air feel “heavier.”  But did you know the air on a humid day is less dense compared more comfortable day with the same temperature?  It may sound odd, even to me at times, but science proves this fact outright.

To answer this question, we have to dust off the old chemistry book.  Now think back – for some of you waaayy back – to your high school or college Earth science class.  In total, Earth’s atmosphere is composed of 78% nitrogen, 21% oxygen, and 1% other gases.  It is estimated water vapor represents 0.40%, not a lot in the grand picture.  However, when we experience a humid day, the amount of water vapor in our local atmosphere is much greater. 

Courtesy: Wikipedia/Booyabazooka

So why is the air less dense, or in layman’s terms, not as “heavy?”  The water molecule, famously known as H2O, has significantly less mass compared to oxygen and nitrogen molecules, the gases that make up 99% of our total atmosphere.  When more water vapor is present on a regional level, more oxygen and nitrogen is displaced to other areas.  Think about this concept by imaging a ship and a sailboat.  Both vessels float, but the ship’s large mass allows it to push away, or displace, more water compared to the dinky sailboat.

Now, I’m not about to go on air and tout or correct how humid air is actually less dense, other than for a learning moment when the weather is slow.  I feel the humidity just like you do on the hot days, waiting for that next front to bring relief, and maybe a little rain too.  Have a great day and thanks for reading my blog!

Posted under Hometown Weather, Weather, Weblogs

It happens almost every year in Wisconsin.  There’s at least one, two-day stretch when temperatures rise above 90 with higher humidity levels.  Many view the weather as uncomfortable, but some ignore the danger lurking just around the corner. 

Sadly, according to NOAA, heat is the number one weather-related killer in the United States.  Each year, hundreds of people die because of dehydration and other heat-related issues.  It comes down to two things: not being able to access cooler locations, and a lack of preparation.  You can do your part to make sure you and your family stay safe this upcoming summer, a summer that is sure to have a number of hot and humid days.

Please keep these tips in mind:

• Never leave children or pets in a vehicle unattended.  In just a few minutes, the dashboard of a car can heat to 200 degrees.
• Always drink plenty of water, even if you are not thirsty.  Dehydration can occur quickly.  Carry water with you.
• Stay out of the sun, preferably in air conditioned rooms in extreme situations.  If you don’t have air conditioning, plan ahead and find a location that will serve as a cooling center for you and your family.
• Don’t forget about your pets!  They get hot too and will need water and shade.
• Remember those susceptible to the heat, especially the elderly and young children.  Make sure they are staying cool.
• Wear lighter clothing and apply ample sunscreen.
• Take it easy!  Physically speaking, don’t push yourself!
• Never leave children or pets in a vehicle unattended and drink lots of water.  Yes, I repeated these tips, but these two are important!

Enjoy this summer and feel free to let us know if you have questions!  Stay tuned for more from Beyond the Forecast…

Posted under Hometown Weather