Just a walk in the rain/snow/mud??? No problem. Duck and goose hunters do it all
the time. Weak spot is the ammo--specifically the crimp and primer. Modern plastic
hulled stuff is DARNED good, but if I were going to leave ammo constantly exposed to
drenching I might seal the crimp and primer with a little clear nail polish.
The gun----walk in the rain no problem. Constant exposure to nasty weather, such
as a gun onboard a boat brings up a few other issues. Many of the super-duper
weatherproof/stainless/wonder finish guns are the same as the plain jane ones internally.
Steel parts, carbon steel springs, nothing special. Constant and prolonged exposure
to a bad environment can turn them into a rusted lump inside. Sounds like that's not
your situation. Just clean it and lube it after your midnight walk on the wild side, and
it should be OK.