Why does Chimamanda Ngozi Adichie end the novel with an image of rain clouds? What are the implications of Kambili feeling that the clouds hung so low she "could reach out and squeeze the moisture from them"? What is the meaning of the novel's very simple

Why does Chimamanda Ngozi Adichie end the novel with an image of rain clouds? What are the implications of Kambili feeling that the clouds hung so low she "could reach out and squeeze the moisture from them"? What is the meaning of the novel's very simple final sentence: "The new rains will come down soon"?