I have kept mine outdoors year round and during winter we sometimes dip into the hard freeze range of 21F (-6C), but they are still sleeping at that time, so I guess they are okay with it, plus it is dry here, our rains are missing in action. There were times it did rain too on cold days, so it makes me antsy about it. I just hope I have made the media as well draining as it can get.
Since your bulbs are awake, maybe just cover with a burlap overnight or back to your mini greenhouse when the temps go down like that and do not water, till the temps stabilize again.
