Commuter #1 and #2 stay outside at home. #1 has a cover over it when it is at home. When at work, it stays inside the office. The nylon cover is not waterproof, but it keeps the sun off (mostly keeps the moonlight off since I ride it to work during the day...)

I would prefer a better, more waterproof cover.

The cover was bought at "Performance" bike shop.

As one mentioned, you can use a cover for a barbecue grill. I looked, but didn't find one that would fit.

When Commuter #2 isn't being ridden, it stays outside under the deck. Some sun is kept off of it, but it gets wet as a fish when it rains.

Oh well...