Won't the cardboard get wet from rain? Up in NYC the snow-rain would not be good for the cardboard, and that could lead to mold.

I am looking for a solution for the figtree on my roof, as I have no way to bring it inside. I wrapped it with some of that mylar bubble wrap that I repurposed from my corner market - it came with salad greens. But alas, even tho it was taped to the pot and tied around with string in several places, the wind took it off. So now my poor fig is exposed to the cold.

Yes, obviously a simple cardboard box will need help in the elements. I put a black plastic bag if reason is eminent, tucking the plastic under the box to further protect it. I put a rock on to if the wins pick up. It is easy to adapt this cover for many weather issues. Further, i may flatten the box and store it for next winter instead of scrambling for boxes when the colds hits.