In the Southeastern United States, where I am so blessed to live, dog days start in early July and don't end until September.
Children were taught the period was so named because it was too hot for dogs to move from the shade where they spent the long, blistering days. We were warned to be especially careful, for everything from bug bites to dew cuts to ear aches were remarkably worse during dog days.
Fortunately, the crops were laid by and growing by then, with harvest several weeks away, so the work would slow down for everyone except the ones preparing vegetables for freezing and canning.
We worshipped the window fans that blew the night-cooled air into our bedrooms enough that we could sleep.
Actually, the term 'dog days' can be credited to the early Romans, who endured these hot, sticky days without air-conditioned houses.
The star Sirius, called the Dog Star because it is the brightest in the constellation Canis Major, rises and sets with the Sun during the hottest days of the year. Naturally, the Romans blamed Sirius for producing lingering, sultry days. Well, they had to blame something.
According to Brady's Clavis Calendarium (1813), Dog Days were popularly believed to be an evil time "when the seas boiled, wine turned sour, dogs grew mad, and all creatures became languid, causing to man burning fevers, hysterics, and phrensies."
I can agree with all that except the hysterical part. Being hysterical would require movement and that would require way too much energy.