It rains in the morning and clears up after school in the afternoon. Why?

Because the weather changes are very uncertain, it is likely to rain in the morning and then clear up at noon.

Especially in the urban areas in the south, it is normal, because the weather in the south changes rapidly because of the climate, and the cities in the north are generally rainy, except in summer. Moreover, in rainy days, because the water vapor in the cloud is limited, it usually doesn't rain heavily for a long time.