Assuming the deck was dry when you sanded it, and the rain was intermittent followed by good sunny weather, I'd say 2-3 days. But to be on the safe side, maybe another day or two.

If it had been raining heavily for two weeks, I would say 2 weeks to dry out- I'm guessing the sanded deck would absorb more water than if it wasn't sanded.

Thanks for the info.

Are you saying 2-3 days on either side of staining? 2-3 days before I stain and 2-3 days after?

Salem