Does the rain in Tomb-Sweeping Day describe the weather or the climate?

I'm not sure. Personally, I think it's the climate (south).

The weather is determined by the climate. South China has a subtropical monsoon climate. In April, the weather gets warmer and the southeast monsoon blows.

In other words, the wind blows the land from the ocean, the air humidity increases, and there is more rain. With Tomb-Sweeping Day, the rainy season has come (south).

The climate is regular, and the monsoon changes with the seasons, so it will rain at this time. Of course, time is not without.

It has changed. It's just small.