I'd find a place to stash it under cover if possible. I had a boat cover and all it was good for was sagging in the rain and trapping moisture in the boat.
I got one from Budge Covers. Came with a lifetime warranty. Very good customer service, and affordable. They're from Kentucky. Good folks and good covers. And they honor the warranty. Mine got ripped twice in 60mph wind. They sent me a new one, with no questions asked, when I filled out the warranty information properly.
Wherever you get it be sure and prop it up I'm the center so water will run off. Depends on what you want and how good. I bought mine on line. 10 year warranty. No matter how good a one you get the sun will eventually dry rot it. I don't have that problem anymore since I bought a carport but I still cover it to keep it clean