Compendium of Knowledge and Trivia Facts: An AO Repository of Sundry Wisdoms
The term "dog days of summer" originated with the Greeks and Romans. The appearance of the star Sirius (the brightest star in the sky) with the rising sun heralded the time when "when the seas boiled, wine turned sour, dogs grew mad, and all creatures became languid, causing to man burning fevers, hysterics, and phrensies"
For the Egyptians, is marked the beginning of the time for the Nile's flooding.
PS...I'm sorry for being a bit crass, please don't ban me.