We live in wet Washington State and I have no trouble storing any of my fabrics in a storage unit all year around, no air conditioning, but we don't get hot for long here and then it is heated to 50 degrees in the winter and my fabrics are A okay. I don't store in cardboard or plastic bags because the cardboard in the damp does draw moisture, which doesn't mean it will ruin it necessarily but may make in smell awful. The big totes have some air getting to it too. Just my thoughts on in. I think plastic bags in the heat will get ruined themselves after very long in that hot of weather.