What does the heat represent?

The intense heat represents the hottest period of the year in most parts of China.

Every year around July 23rd, when the sun reaches longitude 120, it is called "Big Summer". Astronomical experts explained that it was so hot during the "big summer" because since the beginning of summer, the heat absorbed from the ground sun during the day is more than the heat released at night, and the heat keeps accumulating. During the summer heat, the accumulated heat reaches its peak, so the solar term is the hottest in the summer heat.

The ancient summer heat was divided into three periods: "The rotten grass in the first period was firefly; Second, wait for the soil to moisten and cool off the heat; It will be fine when it rains. " The first stage means that terrestrial fireflies lay eggs on hay, and they ovulate at high temperature, so the ancients thought that fireflies were made of rotten grass; The second kind of weather means that the weather becomes sultry and the land is wet. "Three seasons" means that there are frequent strong thunderstorms, summer heat and humidity weaken, and the weather begins to transition to beginning of autumn.