I was wondering the same but then tried the same word order, only with 'raining' instead of 'rains' and it's correct. Now, I think it's maybe even logical....It's raining atm but you won't ever say in English 'It rains there'. You could say 'It often/barely ever rains there', for example.
Nobody here in the UK would say that, I agree, because we get rain in every part of the country, :) but I can imagine some places in the world, where it would be true to say, "In the east it rains", with the implication that the west doesn't get any rain.
That is of course true, but does it make "It rains" wrong here, and if so, how would we say in Dutch, "It rains"?