Three dog days is the hottest day of the year, and it is also a good opportunity to cure winter sickness in summer. Three dog days is a great torture for outdoor workers, so when to go out? Will it be hot after going out?
When does the dog days in 2018 start? The dog days in 2018 start on July 17, 2018.
Dog days in 2018: 40 days in total
July 17, 2018 - July 26, 2018, the first fall, 10 days
July 27, 2018 - August 15, 2018, zhongv, 20 days
August 16-25, 2018, last 10 days
The three volts are calculated according to the lunar calendar, which is between the second half of July and the first half of August. The time of ambush is not fixed every year, and the length of the ambush is not the same. It needs to be calculated by checking the almanac. It can simply use the four word formula 'summer solstice three Geng' to express the date of ambush, that is, from the third 'Geng' day after the summer solstice, the first ambush is 10 days, the middle ambush is 10 days or 20 days, and the last ambush is 10 days.
From the beginning of the summer solstice, according to the arrangement of the days of the GaN and Zhi dynasties, the third day of Geng is the first day of ambush, the fourth day of Geng is the middle day of ambush, and the first day of Geng after the beginning of autumn is the last day of ambush. When there are 4 g days between the summer solstice and the beginning of autumn, the median period is 10 days, and 5 g days is 20 days. From this, it can be concluded that the occurrence of the day of Geng will affect the length of the middle volt, so there are some years with 30 days of dog days and some years with 40 days of dog days.
According to this method, the total number of dog days in 2018 is 40 days.
The reason for the formation of the "three dog days" is that the surface humidity becomes larger, the heat absorbed is more, the heat emitted is less, and the heat of the surface layer accumulates, so it gets hotter day by day and enters the "three dog days". The accumulated heat of the ground area reaches the highest peak, and the weather is the hottest.
In addition, there is more rain in summer, and the air humidity is large. The heat capacity of water is much larger than that of dry air, which is also an important reason for the sultry weather. In July and August, the subtropical high was strengthened. Under the control of the subtropical high, the downdraft inside the high pressure made the weather clear and cloudless, which was conducive to the sunshine, the ground radiation increased temperature, and the weather was even hotter.