Dog days of summer comes from the constellation and star Sirius being present in the sky...and here it is the last day of summer. "What I did on my summer vacation" is the theme of this post. And here is a good article on Sirius and the references of "dog days"
https://news.nationalgeographic.com/2015/07/150710-dog-days-summer-sirius-star-astronomy-weather-language/
