If you are like most people you probably believe that the phrase “dog days of summer” comes from the fact that dogs tend to lay around a bunch when they get really hot. Well duh, we would too if we were wearing a fur coat in the sunshine. But this term actually refers to when the star Sirius becomes visible in the summer sky.
The ancient Romans called the hottest, most humid days of summer “diēs caniculārēs” or “dog days.” Sirius was known as the “Dog Star” because it was the brightest star in the constellation Canis Major. They believed that because Sirius was so bright, it radiated extra heat toward Earth. During the summer, when Sirius rises and sets with the Sun, they thought it would actually add heat to the Sun’s heat and cause hotter summer temperatures.
Sirius is the brightest star you will see in the night sky and the Roman astrologists connected it with heat, drought, sudden thunderstorms, lethargy, fever, mad dogs, and bad luck. Good times, right?
The dog days of summer stretch from early July to mid-August so you still need be on the lookout for roving packs of rabid dogs and strange fevers. We have a week or so of these “dog days” left!