What is the origin of summer solar terms?

Slight summer is the eleventh solar term among the twenty-four solar terms, and it is the end of noon and the beginning of the unfinished month of the dry calendar. When the sun reaches 15 degrees, the festival is held from July 6 to 8 in the Gregorian calendar every year. Summer means hot, a little hot, not very hot. It's getting hotter, but it's not the hottest.

The summer heat began to enter the dog days, the so-called "dog days are hot, three or nine days are cold." The dog days, usually between the light summer heat and the heavy summer heat, are the time when the temperature is the highest and it is humid and sultry in a year. Monsoon climate is the main feature of China climate. In summer, affected by the warm and humid air flow from the ocean, many places in China are hot, humid and rainy. Although the sun is scorching, it is hot, humid and rainy at this time. For crops, the same period of rain and heat is conducive to growth.