the "dog days" of summer? I knew you were curious, so I'll tell you!
It's because the ancient Romans believed that the six or eight hottest
days of summer were caused by Sirius, the brightest visible star in the
earth's sky, called the Dog Star. They called these extra hot days
cuniculares dies, which translates "dog days". So, there you have it.
~~vintage French poster borrowed from google images~~