Why did it get cold after beginning of autumn?

Beginning of autumn is the first solar term in autumn, which marks the official start of the season in Qiu Meng: "Autumn" means that summer becomes cool. When we arrived in beginning of autumn, the phoenix tree began to shed its leaves, so there is an idiom "Autumn is known by falling leaves".

Introduction to beginning of autumn

Beginning of autumn, the 13 solar term in 24 solar terms, is the first solar term in autumn, which falls on August 7-9 of the Gregorian calendar every year. At this time, the bucket handle of the Big Dipper points southwest, and the sun reaches longitude 135. The 24 solar terms reflect the changes of "Qi" in the four seasons. Beginning of autumn is the node where the yang gradually closes, the yin gradually grows, and the yang gradually turns to yin.