Ok so we are getting a new planet called Marinar soon and its supposed to be fairly covered with water, so at least a bit of rain is in order. Also it would be cool if we could make it our version of Seatl-I mean Kamino (except with actual land if were talking Kamino). I would suggest like each MC day it rains for like 3/4 of it or so. If not at least we should get like a few IRL minutes of rain every other MC day or so.
Perpetual rain seems like the only answer.