When do the three summers start?

The third summer begins from Xiao Xia, around July 7 every year. The three summers are discontinuous, with light summer around July 7, big summer around July 23 and midsummer around August 23. There is also a solar term between Great Summer, Minor Summer and Great Summer, that is, beginning of autumn (around August 7th).

The dog days last for 30 to 40 days, with initial lodging 10 day, intermediate lodging 10 or 20 days, and final lodging 10 day. Dog days generally appear from mid-July to mid-August, between summer solar terms and summer solar terms. Ming and Chen Sanmo's "The Complete Compilation of the General Examination of Chronology: A Detailed Explanation of the Twenty-four Solar Terms in a Year" said: "There are three volts in summer, and the third night in summer in May is the first, the fourth is the middle, and beginning of autumn is the last." That is to say, from summer to the third Geng Day in the future to the day before the second Geng Day after beginning of autumn, it is divided into three stages, namely, the beginning, the middle and the end, commonly known as "dog days".