wood is a moisture sponge.... the moisture content in all woods raise and lower constantly, unless it is in a stable inviorement. there is no sealer made that will stop those MC measurements from changing either...furniture, doors, old wood windows, and bows...
so if you have a bow that home is in the desert, or a very dry climate. that bows moisture content may stay at 7-8 percent all year. you take the same bow and hang it in my shop in oregon, and the MC will jump to 12%....if i bring the same bow in the house where we are running the wood stove, it dries it back out again.
the reason fridgid weather blows one bow up, and not the other has more to do with the mosture content in the wood freezing than anything else.when water freezes, it expands...the extremely cold weather effects composite materials in different ways too.... warm.... flexible.... cold... brittle and stiffer.
if i'm hunting in snow and cold weather, that bow of mine goes in the sleeping bag at night with me...