Same here. I ride year round here in the northwest (Oregon) and have not used the cover pretty much for years. I have been known to put it on if I am going to be in a known downpour on the way to work and do not want to listen to the radio or mp3 anyway, or if I am going to leave it outside overnight in the rain.
When I ride to work, I park in a municiple parking lot. Last year, a strong T-storm rolled through during the day & my radio did stop working for a couple of days. This last spring I bought a cover from Cyclemax. http://cyclemax.com/inc/sdetail/86/127001
Now if there is a storm in the forcast, I put the cover on when I get to work.
Like the others, my bike has been through some pretty heavy storms without any radio problems without the cover....that said, I since have installed my cover with gold hinges giving me some more mounting surface for whatever. I cut out the area of the volume & tone controls so I can adjust them without having to life the cover. :waving: