"Dog Days of Summer" Officially End Today

The Dog Days of Summer officially come to an end today. In case you’re wondering, the "dog days" last for 40 days, from July 3 to August 11. They are directly related to the brightest star in the night sky, Sirius, in the constellation Canis Major, or the big dog. Sirius is known as the Dog Star, and we see it clearly illuminating the night sky from early Autumn through early Spring.

However, during this time of the year, Sirius rises and sets with the Sun. During late July, Sirius is in “conjunction” with the Sun, and the ancients believed that its heat added to the heat of the Sun, creating a stretch of very hot, humid, and sultry weather. Actually, the conjunction of Sirius with the Sun varies slightly with latitude, and a gradual drifting of the constellations over time means that they are not in exactly the same place in the sky as they were in ancient Rome.

Although this is typically the warmest time of the year in southwestern Connecticut, the added heat is not due to the added radiation of a far-away star, regardless of how bright it is. The heat of Summertime in the Northern Hemisphere is a direct result of the Earth’s 23.5 degree tilt on its axis. Today's normal high temperature is 82 degrees, just one degree shy of the normal high for late July.

Paul