Why does it always rain on weekends?

More and more people living in big cities are sensitive to find that: in a week's working day, "God" gave a "good face" and the weather was fine; But it often rains on weekends, either in Mao Mao or in heavy rain, which seems to have become a rule. In fact, scientists have noticed this meteorological feature and conducted various studies. Research by meteorologists Randall Cerveny and Robert Bahrain of Arizona State University in the United States shows that there is indeed a weather phenomenon with a cycle of one week, and there is always more rain on weekends than on other days. They believe that air pollution caused by human activities is getting more and more serious from Monday to Friday, which eventually leads to rainy weather on weekends. In fact, the impact of human activities on climate is not a new topic. It is believed that global warming is influenced by the greenhouse effect of carbon dioxide, such as urban heat island effect, and it will also affect the local climate, but no one has noticed the weather changes caused by human activities in the border areas of large-scale regional weather. In some areas, this effect can be compared with the El Niñ o phenomenon. Two meteorologists studied the Atlantic climate satellite data from 1979 to 1995. They found that the ocean as a whole, its rainfall is not affected by which day of the week. But they found that the area near the coast was obviously different. It often rains on weekends in densely populated areas along the eastern coast of China, with 22% more rainy on Saturday than on Monday. The research shows that with the coming of the weekend, the contents of ozone and carbon monoxide peculiar to the two cities also reached the highest value in a week. These pollutants led to the formation of clouds near the coast, and at the same time gained steam and power from the storm center over the ocean, and finally formed rainfall. This 7-day cycle rainfall phenomenon is called Sunday effect, which is attracting more and more attention in some cities.