What is three volts?

Three volts is a general term for initial, middle and final volts. The dog days are characterized by high temperature, low pressure, high humidity and low wind speed.

The dog days appear between midsummer and hot summer, which is the time when the temperature is the highest and it is humid and sultry all year round. The word "V" in three volts has two meanings. First, it means that Yin Qi was forced by Yang Qi to hide underground; Second, it means the weather is too hot to move.

The sleeping time is determined by the combination of solar terms and dry branch dates.

According to the traditional calculation method in China, the third Geng day from summer to the future is the beginning of "initial lodging", the fourth Geng day is the beginning of "intermediate lodging" and the first Geng day after beginning of autumn is the beginning of "final lodging".

The time of accommodation is not fixed every year, and the length of accommodation is also different. You need to check the almanac to calculate it. Simply put, we can use the formula of "Xia San Geng" to express the lodging date, that is, from the third Geng day in Xia Hou, the initial lodging is 10 day, the intermediate lodging is 10 day or 20 days, and the final lodging is 10 day. In ancient China, the "trunk-branch calendar" was popular, and 60 groups of different names were used to record dates with 10 heavenly stems and 12 earthly branches, which were recycled. The day with the word "Geng" is called "Geng Day".

The word "Geng" in Geng Day is the seventh word in "A, B, C, D, E, Ji, G, Xin, Ren, Gui" 10 day, and it is repeated every 10 day. Starting from the summer solstice, according to the date of trunk, the third Geng day is the first, the fourth Geng day is the middle, and the 1 th Geng day after beginning of autumn is the last.

If Geng Day occurs on beginning of autumn Day and two days later, it is 10 days, otherwise it is 20 days, so some years are 30 days, some years are 40 days, and most of them are 40 days. The next year with three days and 30 days is 203 1.