As China has the very long history, so the ancestors have figured out many ways to make record of the weather. With the regular marks, people can know the time and weather correctly. When summer comes, the hot weather begins with the time of Lesser Heat. So people know what they should prepare in the coming hot whether.
In my family's tradition, my mother will cook the Chinese watermelon soup for us. She believes that it can drive away the heat in our body. One time, I doubted that function of this soup, then my mother told me that she didn't cook the soup one time and in that year, she got a fever. So she believed strongly that we should eat the Chinese watermelon soup, or we would get a fever easily.
I admire the ancestors' wisdom. They found a way to record the time without high technology. The found of Lesser Heat helps people to get away from the hot weather and let people prepare some work for their crops. The tradition still works no matter how fast the society develops.