How many days are there in summer?

From summer to the future, the third Geng Day is the first day, the fourth Geng Day is the second day, and the first Geng Day after beginning of autumn is the last day (summer). The first Geng Day is every ten days and the second Geng Day is ten or twenty days.

The specific date of the hot summer is determined by the solar term date and the dry branch date. According to the traditional calculation method in China, the third and fourth Geng days from summer to the future are the start dates of the first (recumbent) and the second (recumbent) respectively, and the first Geng day after beginning of autumn is the first day of the last (recumbent).