FX Impact after rain.

I avoid that at all cost. I carry a folded up trashbag in my back pocket.....and never forget it. I got caught in the rain with a tx200 once......it only stayed wet for about 30 minutes tops. I walked in the house....took the stock off.....and completely disassembled it. Used a whole can of remoil dousing every metal part including down the barrell. The cleanup was the next day.....getting all the old lube out and remoil. Relubed.....put back together. Real pain in the ass. At the very least I would thoroughly clean the barrel in your case. Maybe take the bolt probe out before it flash rusts.
 
Have experience with several fx airguns, a word of cation! The quality of metal is very poor(porouse).In the past being a high quality PB guy I was way too relaxed when it came to moisture on these. This lead into 2 new barrels. My gunsmith inspected the barrels and told me to avoid any kind of moisture at all cost. This is not a bash by any means, all rifles were very accurate until the corrosion kicked in.