Dog Days of Summer

The term Dog Days traditionally refers to a period of particularly hot and humid weather occurring during the summer months of July and August in the Northern Hemisphere. The Old Farmer’s Almanac, considers the Dog Days to be the 40 days beginning July 3 and ending August 11.  

This period of sweltering weather coincides with the year’s heliacal (meaning “at sunrise”) rising of Sirius, the Dog Star. Sirius is part of the constellation Canis Majoris—the “Greater Dog”—which is where Sirius gets its canine nickname, as well as its official name, Alpha Canis Majoris. This was a time of note in ancient Greece, Rome and Egypt, so the history goes back thousands of years.  

It was believed that the dawn rising of Sirius in mid-to-late summer contributed to the extreme weather of the season because Sirius is the brightest star at night, so the combined power of Sirius and the Sun made it swelteringly hot. Diseases spread more quickly and people and animals seemed to go mad. In Egypt, the Nile often flooded at this time, too. It was thought that the heat made everything and everyone act crazy.