As of this past Monday, we are officially in the dog days of summer. No, really: That isn't just an expression. The "dog days of summer" actually refers to an astronomical event.
From early-July to mid-August, the star Sirius (which is represented by a dog in ancient Greek and Roman mythology) appears to rise and set with the sun. As the brightest star in the night sky, Sirius was already associated with light and heat. Its perceived proximity to the sun during the summertime only added to this reputation.
Among the ancient Greeks, Romans, and Egyptians, it was believed that the combined energies of Sirius and the sun made summer's peak as hazy and hot as it tends to be. And, thanks to Sirius' canine characterization, this time of year came to be referred to as the "dog days" of summer.
Beyond sticky and sweaty July weather, the dog days of summer (and Sirius, for that matter) have earned a few other associations, some more negative than others.
The ancient Greeks and Romans believed that actual dogs went wild during this time of year, while humans became listless and lazy. If you ask us, it's hard not to feel listless and lazy when the temperatures are pushing 90 degrees, but who are we to judge our forebears?
Meanwhile, the ancient Egyptians believed that Sirius, known there as Sothis, was responsible for the annual flooding of the Nile. Where the Romans and Greeks considered this star a sign of decline, the Egyptians took it as a signal of incoming good fortune and plenty: Ancient Egyptian farmers depended on the Nile's regular floods to supply them with enough water for the dry season to come.
Looking back on it, we can tell that this one star's activity probably doesn't have that much of an effect on the Northern hemisphere's weather, but the name has stuck all the same. And, if you're looking for an excuse to be extra lazy this July, now you have it.