Putting a can in a gallon ZipLock freezer bag will help prevent moisture fluctuations if the cap isn't perfectly sealed.
I talked at length with the rep from Swiss at a show. He allowed that moisture variations are worse than temperature variations in long term storage of BP. Overall, he said it is pretty stable though. He said he'd run into some old BP that was quite damp. Once laid out to dry, it worked just as it should.
On temp, he said avoid super deep freeze and super heat (like 120+ degrees).
Don't store it in something that cannot release pressure. Those Cabela's or Walmart plastic imitations of Army ammo cans seem like a nice choice. Holds out moisture variations, but would give way easily under pressure.
I hope this helps. God Bless, Marc