Note:  Do not rely on this information. It is very old.

Dog Days

Dog Days, a period of the summer commonly reckoned from about July 3rd to August 11th; by Pliny connected with the rising of the dog star (whether Sirius or Procyon is meant is not clear) which he dates on July 17th. The most unhealthy time of summer frequently, but by no means always, coincides with this period. The ancients attributed great influence over the whole of the animal kingdom to these stars; probably because the heliacal rising of the dog star Sirius, called Sothis by the Egyptians, coincided with the ex-. treme of the overflow of the Nile. Of course the whole notion is a survival of astrological superstition.