Why do we call it the dog days of summer?
We often say the middle of July through the first week of August is called the dog days of summer.
It actually doesn't have anything to do with your pet.
Ancient Romans believed that Sirius, the dog star, added heat along with the sun this time of the year. Sirius actually rises and sets the same time the sun does. We of course know that a faraway star like Sirius would not add additional heat but the phrase still continues this time of the year.