This poem expresses a feeling of joy. The theme is to highlight "the first rain of spring", which gives people a programmatic expectation from the title. (Of course it is not easy to write this kind of poem well. The only one I can remember is "Spring Rain" by Ji Xian)
The first paragraph of the poem forms a sharp contrast between winter and spring rain. Starting with a depressing feeling so that most people can relate to it. The word "chest" is completely the language of poetry. Bitterness and sweetness are synaesthetic techniques.
The second paragraph is about the agility of rain,
The third paragraph is about the softness of rain,
The fourth paragraph is about the praise of rain, A kind of vitality for all things.
That’s it for now. I don’t know if this is a model of appreciation. It’s really painful to explain the concepts. If it's not appropriate, please ask. I'll risk my life to make it up to you when the time comes.