Beginning of autumn is the thirteenth of the twenty-four solar terms and the first solar term in autumn. It refers to the southwest of Li Dou, where the sun reaches longitude 135 degrees every year on August 7th or 8th in the solar calendar, and crosses here.

Beginning of autumn in 2022 is on August 7th.

The change of the whole nature is a step-by-step process, and beginning of autumn is the turning point when the yang gradually closes, the yin gradually grows, and the yang gradually becomes cloudy. In nature, everything begins to mature from lush to bleak.

Beginning of autumn doesn't mean the hot weather is over. Beginning of autumn is still in a hot period, but it is not hot yet. The second solar term in autumn (summer) has come out, and the weather is still very hot in early autumn. As the saying goes, "It's hot in dog days" and "It's hot after beginning of autumn", and there is at least one volt of hot weather after beginning of autumn.

According to the calculation method of "three volts", "beginning of autumn" is often still in midsummer, that is to say, the heat is not over, and the real coolness usually comes after the Millennium solar terms. The cold-hot watershed in beginning of autumn is not a solar term.