Attested in English since 1538, from Latin dies caniculares, translated from Ancient Greek; originally a reference to the hot summer days (in the Northern Hemisphere) when Sirius (the Dog Star), in Canis Major, rose and set with the Sun (heliacal rising). The Greeks also made reference to these "dog days", and for the ancient Egyptians, circa 3000 BCE, the rising of this star coincided with the summer solstice and the start of Nile flooding. The "dog" association apparently began here, as the star's hieroglyph was a dog, a watchdog for the flooding of the Nile.
- The days between early July and early September when Sirius (the Dog Star) rises and sets with the Sun.
2013 August 17, “A rickety rebound”, in The Economist, volume 408, number 8849:
- The dog days of August have often spelled trouble for the world economy. In 2011 America’s politicians flirted with default and the euro seemed to be heading for collapse. The summer of 2012 brought another bout of euro angst and depressing evidence that many emerging economies had stalled. But so far this season the good news has outweighed the bad.
- Hot, lazy days.
- A period of inactivity, laziness, or stagnation.
- "Dog days" have long carried an association as the hottest, most stagnant, and unwholesome time of the year, usually July 3 to August 11, but variously calculated, depending on factors such as latitude, historical period, or whether the lesser star Procyon is also reckoned. Specifically, the heliacal rising of Sirius has shifted down the calendar with the precession of the equinoxes, making the exact dates of the "dog days" significantly distinct now from those in former times.