Which dog days are the hottest?

Although it is already very hot in dog days, it can be divided into three days: the beginning, the middle and the end, with the hottest day in the middle. During dog days, the surface humidity increases, and more heat is absorbed every day, less heat is released, and the surface heat is accumulated. When it is in the middle, the heat accumulated on the ground peaks in the middle, releasing the most hot air, so it is the hottest in the dog days.