#Summer life check-in season# I believe everyone has noticed that sometimes the time of the three volt days is different, in fact, there is no accurate date for the three volt days, and the number of days is also established between 30 days and 40 days, which is actually related to the middle volt of the three volt days, so why does the middle volt have 10 days and 20 days? Let's take a look together!
Why does the medium volt have 10 days and 20 days
Because every year the three volt days are different.
In fact, there is no exact date for the three volt days, and the number of days is established between 30 and 40 days, and when there are 4 Geng days between the summer solstice and the beginning of autumn, the middle volt is 10 days, and the appearance of 5 Geng days is 20 days. The appearance of the day will affect the length of the volt, so there are cases of 30 days in some years and 40 days in some years.
In ancient times, the mainland popularized the "dry branch era and day method", using 60 different sets of names made by matching 10 heavenly stems and 12 earth branches to record the days and recycle them. Every day with the character Geng is called Geng Day. The character "Geng" on Geng Day is the seventh character in the 10 heavenly stems of "A, B, C, D, E, H, GENG, XIN, NON, and dec", and Geng is repeated every 10 days. From the summer solstice, according to the arrangement of the dry branch days, the third geng day is the first volt, the fourth geng day is the middle volt, and the first geng day after the beginning of autumn is the last volt.
The establishment of the three-volt day is based on the third day of the summer solstice, and the date of the middle volt is also based on this. The third Geng day from the summer solstice is the first volt, the fourth Geng day is the middle volt, the first Geng day from the beginning of autumn is the last volt, which together is called three volts, and when there are four Geng days between the summer solstice and the beginning of autumn, there is a middle volt; When there are five geng days between the summer solstice and the beginning of autumn, there are two middle volts.
Why is medium volt the hottest
At the beginning of the three-volt day, the hot weather is just beginning and the ground absorbs more heat than it releases. However, as time goes on, the heat absorbed by the ground continues to accumulate. In the middle of a three-volt day, the accumulated heat on the ground reaches its maximum. Therefore, the three-volt mid-volt is the hottest time of the year. In addition, there is a lot of rain in summer, the air humidity is high, and the heat capacity of water is much greater than that of dry air, which is also an important reason for the sultry weather. In July and August, the subtropical high intensifies, and under the control of the sub-high, the sinking air flow inside the high pressure makes the weather clear and cloudless, which is conducive to sunlight exposure, and the ground radiation warms, and the weather is hotter.
There is a saying in the countryside called "the middle volt sky, the depression does not dry", which means that after the middle volt, the depression must be kept moist for a long time, once the depression is dry, the soil in other places should be dry, so in the middle volt should rain for three days and two heads, which can not only avoid soil drought, but also play a cooling role.
During the middle volt period under the action of high temperature, crops accelerate metabolism, need a lot of water, rain is sufficient to be conducive to the benign growth of crops, rural saying is good "moderate rain, hoard more rice", it can be seen that rain during the middle volt is very important for agricultural production.
This year's 20 days of mid-volt, which is equivalent to the rural "double volt", not only means that the hot weather is about 10 days longer than in previous years, but also needs to strengthen the prevention of natural disasters during this period.