I can’t think of any other ‘it’ that is meaningless. ‘It’ normally refers to something in the sentences context. But in that and in the sentence ‘it rains’ there is nothing that ‘it’ could refer to. The sky doesn’t snow, the weather doesn’t snow and neither do the clouds.
Snow is god scratching his dandruff onto us and rain is him pissing 😌🙏 hope this helps