What do you mean by dog days? What are they dog days?

First, middle and last. Dog days are miscellaneous solar terms other than the twenty-four solar terms. In order to adjust the climate, the ancients summarized the solar terms in the hottest period of the year according to the laws to be followed. Because the time span is long, it does not belong to the category of 24 solar terms, so the dog days are miscellaneous solar terms. Dog days are divided into three sections, the first section, the second section and the last section, dog days. The dog days appear between midsummer and hot summer, which is the highest, wettest and sultry day 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. It can be understood that "V" means that it is too hot to have a rest. The dog days are the hottest thirty or forty days in a year in the Central Plains. The dog days are calculated according to the lunar calendar, and the solar calendar is from mid-July to early August.