I left my 1989 J outside for ~2 years in South Florida and bought a full set of custom Bruce covers (fuselage, tail, wings). I highly recommend Bruce Covers as well, they are excellent and are the only ones I'll buy for aircraft now. They were a pleasure to do business with as well. South Florida is a lot different than the NW US but I'll give you my experience on keeping a J outside. I'm only the fourth owner of my aircraft, she was apparently hangared by the other three owners in the NE and she still has her original paint job from 1989. Keeping the plane outside was the worse decision I ever made. If I had to do it over again I probably still would as my dream plane came available and I'm glad I bought her, but it cost me a lot of stress and money. I will never own an aircraft again, regardless of where I live, unless I have a hangar for her and if I couldn't hangar my baby anymore I'd unfortunately rather sell her then keep her outside. The Bruce covers really help with the sun and light rain but the rain still gets into the tail and at least in FL the humidity from the rain evaporating doesn't help either. My paint job started to self destruct outside within months that I had her outside, I had lots of small mechanical issues from water intrusion too (issues with light connectors, superficial corrosion, speed brake problems, etc.). I have her in a hangar now and the plane is very dependable and I have no problems and MX doesn't get too crazy anymore. I'm sure other places aren't as bad as South Florida (we do have a reputation as being tough on metal aircraft) and I know others who haven't had as many issues keeping their planes outside, but it makes a huge difference having the plane hangared. I used to have a lot of issues with wasps and spiders making nests in the plane too, which was fun... Just my 2 cents...