The Dog Days of Summer are technically the hottest, sultry days of the summer, when air is stagnant. Named by the Romans (although the Greeks had also called this period dog days) for the time from late July to early Sept. The brightest star in the constellation Canis Major (large dog) Sirius, the dog star, rises with the setting sun at the end of July/beginning of August. The Romans designated 40 days, 20 before and 20 after this event, as the dog days of summer, and sacrificed a brown dog in order to appease/prevent hot weather (they believed the earth received heat from this star, which combined with the sun at this time was responsible for the hot days of summer.).
The old farmers almanac has the dates at 3 July to 11 August. Seems to be slightly longer this year, although cooler weather ahead, after all these violent storms!
The Patron saint of dogs, St Roch has his feast day on August 16th, which was during most European dog days. Hello Rochester!
“It was an ‘evil time when seas boiled, wine turned sour, dogs grew mad and all creatures became languid” Brady’s 1813 Clavis Calendarium