I have discovered that when you ask people what the term “Dog Days” means, you will get a variety of answers.  Such as:

“That’s the time of year when it’s so hot you see dogs
lying on porches and under shade trees.”

“It’s the hottest part of summer”

“Dog Days is the time of year that dogs are more likely to get rabies
so you have to watch animals very closely.”

And my favorite answer:

“That’s when it’s time to go shopping because all
the stores have really good sales”

All of these answers are correct, at least in part,
but I did a little more research on the subject.

Webster defines “dog days” as:

1.  The period between early July and early September when the hot sultry weather of summer usually occurs in the northern hemisphere
2. A period of stagnation or inactivity

As I searched further, I found that dog days originated back in ancient times.  The stars in the sky could be seen much more clearly back then because there weren’t any streetlights or smog to obscure the view.  The people would pick out the brightest stars and draw lines between them much like we teach children to “connect the dots”; only in this case it was “connect the stars”.  As the more dominant stars were connected, different images were created such as lions, bears, and even dogs.  These connected stars became known as constellations and the Canis Major is the one that depicts the dog.  The brightest star in this constellation is Sirius or the “Dog Star”.

Since the Dog Star was so bright in the summertime, mainly from early July through August, the people in ancient times thought that it’s brightness added to the heat of the earth.  This was why they thought that it was so hot during that period of time.  The heat of the sun, plus the heat of the Dog Star was thought to push up the earth’s thermostat and cause
us to hunt a shade tree and a cool drink.

Today we know that the Dog Star does not cause the hot summer at all;
the heat is caused by the tilt of the earth.

I ran across a humorous description of hot weather the other day that explains Dog Days in words we all understand.  It is the time of year that it is so hot that:

-The birds have to use potholders to pull worms out of the ground.

-The potatoes cook underground, and all you have to do to have lunch is to pull one out and add 

 butter, salt, and pepper.

-Farmers are feeding their chickens crushed ice to keep them from laying hard-boiled eggs.          

-The cows are giving evaporated milk.

-The trees are whistling for the dogs.

-You eat hot chilies to cool your mouth off.

-You can make instant sun tea.

-You learn that a seat belt makes a pretty good branding iron.

-The temperature drops below 95, you feel a bit chilly.

-You discover that in July, it takes only 2 fingers to drive your car.

-You notice the best parking place is determined by shade instead of distance.

-Hot water now comes out of both taps.

-Your biggest bicycle wreck fear is, "What if I get knocked out and end up lying on the pavement

 and cook to death?"

-You realize that asphalt has a liquid state.