What are the hottest days of the year?

July 20th to August or so 15. The dog days are between the light summer heat and the heavy summer heat, which is the highest, wettest and sultry time of the year. "The third Geng in the summer counts several heads", which is the basis for establishing the initial crouching. From the summer solstice to the third Geng day, it began to squat. The "Geng Day" here refers to the days prefixed with "Geng" in the ancient "Ganzhi Jiri Law". The date of Geng Day is changeable, not fixed.

In ancient China, time was recorded by combining heavenly stems and earthly branches. The number of heavenly stems is 10, which is A, B, C, D, E, Ji, G, Xin, Ren and Gui, and the number of earthly branches is 12, which is Zi, Ugly, Yin, Mao, Chen, Si, Wu, Wei, Shen, You and Yi. Heavenly stems and earthly branches, Jia Zi, Yi Chou, Bing Yin, Ding Mao, etc. And cross-match 60 times, so it is called 60 flowers. "Three Geng" means meeting three "Geng" characters, and the third Geng Day will be the first time. Because the number of heavenly stems is 10, there is a Geng Day every 10 day, such as Geng Zi Day, Geng Yin Day and Chen Geng Day. 365 days a year (366 days in leap year) is not an integer multiple of 10. One day this year is Geng Day, and next year is not necessarily Geng Day. Due to the uncertainty of Geng day, the date of entering the hole is different every year. Voltage is divided into initial voltage, intermediate voltage and final voltage, which is called three volts. The dog days are the hottest period of the year, because the nights are getting shorter and shorter, the days are getting longer and longer, and the sunshine is close to direct sunlight. But the summer solstice is not the hottest time, because at this time, a large part of the heat absorbed by the ground radiates at night. But it absorbs more heat and dissipates less heat every day, and it gets hotter every day. It will be the hottest in about 20 days to three volts. The date of the dog days is from the summer solstice to the third Geng Day, which is the first lie, the fourth Geng Day to the fifth Geng Day is the middle lie, and the second Geng Day after the first Geng Day to beginning of autumn is the last lie. Every Geng day is 65,438+00 days apart, and the number of mid-festival days is not fixed. There are four Geng days from summer solstice to autumn, with 65,438+00 days in the middle, five Geng days and 20 days in the middle. V means summer. From the summer solstice, the days begin to get shorter and the nights begin to get longer. There is a cold factor lurking in the middle of heat, so the name "Fu" is very scientific.