Dog days
The expression dog days refers to the hot, sultry days of summer, originally in areas around the Mediterranean Sea, and as the expression fit, to other areas, especially in the Northern Hemisphere.
The coincidence of very warm temperatures in the early civilizations in North Africa and the Near East with the rising, at sunrise (i.e., the heliacal rising), of Orion's dog, the dog star Sirius, led to the association of this phrase with these conditions, an association that traces to the Egyptians and appears in the ancient written poetic and other records of the Greeks (e.g., Hesiod and Aratus) and the later Romans (including Homer, in The Iliad).
The expression is used in prose literature, poetry, and song and album titles.
General description
The dog days are the hottest, most uncomfortable part of the Northern summer. The American weather and farming annual, The Old Farmer's Almanac, explains that "[t]he phrase 'Dog Days' conjures up the hottest, most sultry days of summer," coinciding with the heliacal rising of Sirius, the dog star, in the constellation Canis Major. While the correlation between the hottest and most humid weather of the year with this specific calendar period has not survived the broadening of weather understanding and communications to global, the correlation of the rising of Sirius with extreme heat has been sufficient in enough climes in the Northern Hemisphere such that the association of dog days "with hot, sultry weather was made for all time."
