Junior high school geography, since the rainy season will go on with time, is it that the rainy season in the south is dry in the north, rainy in the north and dry in the south?

Not necessarily/possibly

Indeed, during the rainy season in the south, most of the time in the north is spring drought; The north is in rainy season, while the south is in summer drought.

However! The actual weather system will certainly not run according to the textbook.

In the rainy season in the south, the north is still controlled by the winter wind. During this period, if there is a strong southwest airflow northward, frontal precipitation can still occur in the north. As the saying goes, "Spring rain is as expensive as oil", which means that it doesn't rain in the north (especially in the North China Plain) in spring, but it is valuable.

In summer, when the rain belt moves northward to North China, the middle and lower reaches of the Yangtze River and South China are under the control of subtropical high. But in fact, the subtropical high affecting China is only the western edge of the northwest Pacific subtropical high, which is only a branch of Hawaiian high. Therefore, whether the subtropical high is stable and strong (sometimes there will be short-term strong convective rainfall at the edge of the subtropical high in the afternoon) and whether there is any movement in the equatorial convergence zone (monsoon trough and typhoon system) in the south will affect the rainfall in the south during the summer drought.

So what you said is only a general situation, but it must be remembered that the development of weather system is not recorded in textbooks, but there will actually be many changes.