sanding in the rain

Hey guys,

im just about ready to start prepping my car for paint. Im going to be sanding it, but not down to bare metal...the problem is that my car is outside and cannot be garaged...if i sand down the car from 80 grit all the way to 320 or 400 wet and it sits outside, would anything bad happen to the paint? how about if it rains? Like i said im not going down to baremetal and any bare metal i would obviously cover, but like i said im worried about the rain touching it since this will be over the course of a few weeks. any help would be great