Climate and Weather


Why are the hot, humid days of summer called “dog days”?

This period of extremely hot, humid, sultry weather that traditionally occurs in the Northern Hemisphere in July and August received its name from the dog star Sirius of the constellation Canis Major. At this time of year, Sirius, the brightest visible star, rises in the east at the same time as the sun. Ancient Egyptians believed that the heat of this brilliant star added to the sun’s heat to create this hot weather. Sirius was blamed for the withering droughts, sickness, and discomfort that occurred during this time. Traditional dog days start on July 3 and end on August 11.


This is a web preview of the "The Handy Science Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App