The difference between three volts and the last volt. When is the dog days?

1, three volts includes the last volt and is one of the three volts. Three volts is the general name of the first volt, the middle volt and the last volt, and it is the hottest season in a year. The dog days appear in the Gregorian calendar from mid-July to mid-August every year, and its climatic characteristics are high temperature, low air pressure, high humidity and relatively low wind speed. "V" means being forced to hide underground. Three volts can be divided into initial volts, intermediate volts and final volts, and their dates are determined by the coordination of solar terms and solar terms in the dry branch calendar.

2. According to the traditional calculation method in China, the third and fourth Geng days from summer to the future are the first (head) and middle start dates respectively, and the first Geng day after beginning of autumn is the last first day. Because every Geng day is 10 days apart, the stipulated time of the first day and the last day is 10 days. Because the third Geng day (the first autumn) after the summer solstice solar term appears sooner or later, the number of days in autumn is long or short, which may be 10 or 20 days.