Every year around August 23rd (August 22nd-24th), it is the summer heat of the 24 solar terms when the sun reaches150. Summer is a solar term that reflects the change of temperature. "twenty-four solar term" said: "Go, go, and the summer heat will stop here." "Chu" means termination, indicating that the heat is about to pass, the summer heat will end on this day, and the temperature in most parts of China will gradually drop.

Being in summer is not only different from mild summer, severe summer, slight cold and severe cold, but also represents the transition from hot to cold. In the summer season, the temperature has entered a significant stage of change, and it has dropped day by day, and the summer heat is no longer pressing.

This change in festivals is naturally reflected in farming. A large number of practical proverbs left by the ancients, such as "an autumn rain and a cold weather", "beginning of autumn is cool in the summer" and "it's not coming in the summer heat", are direct descriptions of climate change in the summer heat season.