What do you mean a few days?

Entering volts means entering "three volts".

There is a folk proverb, "The first night falls in summer", which is the basis for establishing the first autumn. The almanac stipulates that "the number of volts starts from the third day of summer", that is to say, "it starts to count down from summer" and begins to fall on the third "Geng Day".

The dog days, which appear between the light summer heat and the hot summer heat, are the time when the temperature is the highest and it is humid and sultry in a year. Three volts can be divided into initial, middle and final volts, and its date is determined by the coordination of 24 solar terms and the dates of dry and branch. After "entering the volt", many places in the country will enter the continuous high temperature mode.

The traditional almanac stipulates that "counting from the third Geng day in summer", that is to say, "counting down from the summer day until the third Geng day" is about to begin to dormant. The "Geng Day" here refers to the days prefixed with "Geng" in the ancient "Ganzhi Jiri Law". "crouching" means being forced to hide underground; This also means that it is too hot to move.

Date calculation:

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. 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 accommodation is different every year.