Good points above.
Don't let the battery freeze, even when not in use when that may be more likely. If you think it may get that cold, stick a small disposable self-adheasive heat-therapy pack on it, which should be good for ~6hrs or so. I pick them up at the dollar store to stick on myself for cold weather camping.
BTW, storage for optimal LIion longevity is ~40deg F, at ~50% charge.