When is the dog days? Was it hot at the beginning of the dog days?

The dog days of 1 and 202 1 start on July 2 1 and end on August 19, totaling 30 days.

The dog days are the hottest, wettest and sultry days of the year. The so-called "dog days" refers to the "dog days" of the lunar calendar, which is the hottest time of the year. "V" means it's too hot to move. But the dog days are called "dog days" because there are many cold factors. The dog days are the hottest thirty or forty days in a year in the Central Plains. Sanfu is calculated according to the lunar calendar, from mid-late July to early August in the solar calendar.