that's tough to say... i just remember it was a very cold, very long winter... i found some records on NOAA website that show we reached record lows on 2 days. -7 deg F on January 13, 2013 22 deg F on April 2, 2013 so that can give you a small indication of my winter. these Hippeastrum were definitely below freezing. they were bone dry, too, and i think that's how they survived. The bulbs of Hymenocallis did not survive. Dennis in Cincinnati