What does "dog days" mean?
Hot, sultry summer weather; also, a period of stagnation. For example, It's hard to get much work done during the dog days, or Every winter there's a week or two of dog days when sales drop dramatically. The term alludes to the period between early July and early September, when Sirius, the so-called Dog Star, rises and sets with the sun. The ancient Romans called this phenomenon dies caniculares, which was translated as “dog days” in the first half of the 1500s.
Learn more about dog days