No garage for my 'bike... it sleeps at the side of the house, been like this for some 20 years, as different bikes have come and gone.
I have an old sweat shirt with the arms cut off, and the holes left by doing this, sewn up, to place over the windsreen first. Then a soft none scratch cover goes over the 'bike, then a nylon waterproof cover, then a heavy duty plastic cover goes over the top of the lot. Sounds a bit faffy but only takes five minutes.
If it get's windy I just throw a long strap round the lot, about where the riders seat is, and pull tight. The kind of strap you can get for free from your local friendly BMW dealer, they tie down the new 'bike's in their crates
The 'bikes have never suffered and are kept like new. Any one that pops in to this thread that knows me will confirm that you wouldn't know the difference from my 'bike to a garaged one... some respects kept better.
My 1150GS for instance did 83,000 miles in three years, was used through three winters... and looked as good as new
So don't worry about it sleeping outside... just ride it and love it