Ans: We all know that weather is a major factor in this whole sanding process, and we should try to avoid rain at any cost. But weather can be unpredictable sometimes, which raises the question of what happens when it rains on your sanded deck. As I mentioned before, sanding is mainly used to smoothen the deck and open up the pores to absorb the new stain afterward. Unfortunately, due to rain, what happens is that your deck absorbs the moisture, and it can raise the grain. So, if it rains after you've sanded your desk, either you have to dry the deck thoroughly for a day, or you can lightly sand the deck again.