storing bike outside - avoiding trapped moisture and rainfall (bike covers)
You know, I worry that marketing firms have brainwashed the entire world into believing that you need to spend a lot of money on fancy materials that are waterproof and breathable. Honestly, just spend a few pounds on a poly tarp and your bike will stay as dry as the day you bought it. Just be sure that you take the bike out to give it some fresh air each day so that you don't have to worry about condensation building up and causing problems. You'd still have to do this anyway even if you bought something expensive, no matter how breathable the salesman promised you it would be.