On this day, it officially entered the summer heat, that is, the dog days, and July 1 1 day-July 20 was the first day. The third Geng of the summer solstice counts the head, which means that counting from the summer solstice to the third Geng day is the day of the head. Four Geng days to the fifth Geng day is middling, and the first Geng day to the second Geng day after beginning of autumn is terminal, which is the so-called "three volts".

The dog days are the hottest period in a year, because the nights are getting shorter and the days are getting longer, and the sunshine is close to direct sunlight. The third Geng day after the summer solstice is the first lodging, with a time of 10 days, and the time of lodging is not fixed every year. It is the hottest at the beginning and the hottest at the end. As the saying goes, heat is in the middle, and the most prominent feature of the middle is "heat". Moreover, it is "hot and humid" and the "sauna" weather makes it difficult to breathe, as if you were in a big steamer.

Incubation temperature

After entering the night, the humidity of the ground becomes higher, and the ground absorbs more heat every day. Less heat is emitted, and the heat on the surface of the ground accumulates, so it gets hotter every day. When entering the midrange, the heat accumulated on the ground reaches the highest value, and the weather is the hottest. The dog days appear in the summer heat and beginning of autumn, which is the highest temperature, humid and sultry day in a year.

The so-called "dog days" refers to the "dog days" of the lunar calendar, which is the hottest period of the year. But the dog days are called "volts" because there are also many cold factors. The dog days are the hottest 30 or 40 days in a year in the Central Plains. The dog days are calculated according to the lunar calendar, which is from the middle and late July to the early August of the solar calendar.