I learned exactly what is meant by the "Dog Days of Summer" a few years ago from a listener who corrected me on Big Frog 104. To begin with, we have plenty of Frog Days of Summer left, so let's see what makes a dog day a dog day.

According to Wikipedia:

"Dog Days" (Latin: diēs caniculārēs) are the hottest, most sultry days of summer. In the northern hemisphere, they usually fall between early July and early September. In the southern hemisphere they are usually between January and early March. The actual dates vary greatly from region to region, depending on latitude and climate. Dog Days can also define a time period or event that is very hot or stagnant, or marked by dull lack of progress. The name comes from the ancient belief that Sirius, also called the Dog Star, in close proximity to the sun was responsible for the hot weather.

In Ancient Rome, the Dog Days extended from July 24 through August 24 (or, alternatively July 23-August 23). In many European cultures (German, French, Italian) this period is still said to be the time of the Dog Days.

The Old Farmer's Almanac lists the traditional timing of the Dog Days as the 40 days beginning July 3 and ending August 11, coinciding with the ancient heliacal (at sunrise) rising of the Dog Star, Sirius. These are the days of the year when rainfall is at its lowest levels."