May 5th to 7th of the Gregorian calendar is "Long Summer" every year. When we enter the long summer, everything is thriving and officially enters the annual summer climate. In the Book of Rites and the Moon Order, Chang Xia explained: "Insects come out, melons grow long, and bitter vegetables show." This is the so-called third-class in Changxia: "First-class cockroach sound, second-class earthworm out, third-class melon sound." This passage describes that in the long summer, frogs can be heard chirping in the fields at first, then earthworms can be seen digging in the soil, and then the vines of melon begin to climb and grow rapidly.
The original meaning of "Duan" in "Dragon Boat Festival" is "Zheng" and "Wu" is "Zhong". "Dragon Boat Festival" and "Chiang Kai-shek" are also right, and noon on this day is right in the middle. The ancients took heavenly stems and earthly branches as the carrier, and the heavenly stem carried the way of heaven, and the earth supported the way of the earth. Heavenly stems and earthly branches was established to contract the fate of heaven and earth, and the times are universal in heavenly stems and earthly branches.