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.
That somehow feels right. I still kind of want some phrase that you could substitute for it though. The most correct feeling thing I could think of are seasons as in ‘the summer rains’. But from a logical standpoint a concept that is defined by humans producing something material doesn’t really make sense since a concept isn’t material.