Well, I guess it depends on what it is and what it's stored in. My "studio" is actually my screened in porch. It has plexiglass windows that go up during the winter, but it still gets pretty cold out there. I have my whole desk setup out there and all of my supplies are in cabinets or on top of the desk. So far I haven't had anything really go wrong in the winter. Mostly I have issues in the summer when it gets humid, but I haven't had to actually throw anything out. And most of my problems are AFTER I use a product, because it takes so long to dry! Lol! My acrylics are the same consistency as they have always been. My hair supply is totally normal. Spray sealants work just fine still. Airbrush still...airs? You get the point. If you have everything boxed, I have a feeling you'll be ok. If you have some expensive supplies that you're particularly worried about I would store them separately inside just to ease your mind. BTW, I live in NC and last winter was pretty mild (no snow) but we did get below freezing often. Is it in the 30's every night where you are? And what kind of paints do you have? Most of mine are Liquitex and they held up like champs!