Why is it raining in the north and not in the south in the same sky?

Regarding the origin of Shun, a chronological history book, Bamboo Chronology, was written in 299 BC during the Warring States Period. "Emperor Shun has a Yu family" said: "Mother said that she was born in, holding a board, and seeing a big rainbow is meaningful." When my mother was working in the field, she saw a rainbow in the sky and became pregnant with Shun. In fact, various versions of the legend about Shun say that Shun's mother was born with a sense of phoenix. Legend has it that in the thirty-ninth year of Emperor Yao, that is, one night in 2 174 BC, Han Deng, who lived in Xu Yao, had a dream. In the dream, there is a very beautiful big bird. Its head is like a wild goose, its back is like a unicorn, its neck is like a snake's neck, its tail is like a fish's tail, its chin is like a swallow, and its mouth is like a chicken. It is covered with colorful patterns. The big bird twittered around a buttonwood tree, spread its wings after the dance, flew to Gripen, stopped on her abdomen and disappeared. I got pregnant after hugging Deng. In the 40th year of Emperor Yao, that is, on the day of 2 173 BC, astronomical wonders appeared in Xu Yao, Zhu Feng. There is no cloud in Wan Li in the morning. In the morning, all of a sudden, dark clouds are gathering, lightning and thunder are thundering, and the rain is pouring down. At noon in the afternoon, the heavy rain stopped and the sun overhead was held up by thick clouds. At this time, unprecedented astronomical wonders appeared in the sky: rainbows appeared in the east, south, west and north directions at the same time. The common people know a proverb: the east rainbow is sunny and the west rainbow is rainy, and the south rainbow is cloudy and the north rainbow is crying. It means the rainbow in the east is sunny, the rainbow in the west will rain, and the rainbow in the south is foggy. If the rainbow appears in the northern sky, it must be disastrous weather, either the sky collapses or man-made disasters. It is not surprising that rainbows appear in different directions at different times and seasons. However, there are four rainbows in the sky at the same time. Four rainbows are like four sedan chairs, which lift the sun alive. What is even more strange is that this colorful bridge made of four rainbows just surrounds Weiyao Village in the center. People have never seen such a spectacle and have heard of it. In the village, men, women and children ran to the open space by the river to watch the excitement. Only Gripen, who is pregnant for more than ten months, stays at home and sleeps. When the four rainbows in the sky disappeared, I saw big birds with colorful feathers in the misty hands of sleeping on the bed, and not one, but a group, with only towering crowns and long tail feathers, colorful and shining, dancing and singing around the bed. Holding Deng happily for a while, a baby cried vaguely and gave birth to a boy. This is the later Shun Di. About the connection between Shun Di and Phoenix, Shan Hai Jing? History books such as Wild South Classic, Shangshu, Songshu, Luoshu, Biography of Liu Xiaozi, and Historical Records are all recorded. Shun Di had an indissoluble bond with Phoenix all his life. Legend has it that Shun Di is the embodiment of the Phoenix, which will accompany Dashun all his life. China culture regards dragons as masculine beauty and phoenixes as feminine beauty. Phoenix is a legendary bird that is good at singing and dancing, virtuous and wise, noble and beautiful. People associate it with Phoenix, which reflects the Chinese nation's incomparable respect for Shun.