As long as you keep everything dry, all should be fine. Actually, electronics work better the colder it gets. Thats why scientists get electronics stuff real cold to see what their ultimate performance is, like getting integrated circuit chips to absolute zero as they run them.
The hotter electronics get, the more problems you will have. That's why computers need fans, and why stuff like stereos and cable boxes have louvers, so the heat can escape.
But if you stuff is just sitting around without you powering any of it up, just make sure you keep it dry. Then the temps shouldn't affect them.