I wouldn't tempt fate by cheaping out, the humidity and temperature swings will still be a problem even when freezing isn't. I tried this once in the mid-Atlantic climate zone around Washington DC with a variety of different items for about 2 years, and regretted the mistake. Now my position is, if it's valuable to you and it isn't designed to live out of doors, make sure it's climate-controlled; not to do so is to be penny wise and pound foolish.
