I once flew a Cub through light rain that I couldn't avoid. I ruined the lovely varnished finish that had taken me a week to apply, polish and balance....... Fortunately the prop had a brass leading edge which protected the wood. Rain has also ruined the paint on the steel prop on the Auster, it also showed me where all the leaks are.
Ah well it's a good excuse to get the prop off and check the pitch.
As somebody commented the noise is more instantly appreciated than any great loss of viz (in light rain at least) even in a 70 mph Cub.