I built a canopy in the back corner of my yard to store a few bikes. For instance the winter bikes go back there during the summer, to get them out of the way. It's not weather proof by any means. The main deterioration that I've noticed is that plant matter such as pollen from the surrounding trees sticks to them, so they tend to get dirty, but are otherwise un-damaged and easy to clean up.

I've always believed that bikes are a lot less delicate than people tend to think. On the other hand, direct sunlight damages paints and plastics, as does extreme heat.

I think if you're under an awning, you should be OK. You could always drape something like an old sheet over them. It doesn't have to be waterproof.

I'm in a neighborhood where I don't worry about thieves, and if they wanted my bike, they'd have to bring an angle grinder to cut through... the weeds.