I'm in northern Wisconsin and its been below freezing at night for the last several days. Even got down to 25 one night a few weeks ago.
They are more hardy then you think. Dont take the plant until it's done or you absolutely have to because you have lost the fight to mold etc.
Nothing is worse then weak weed because it is premature.
When the temp drops just make sure that day you water with warm water....and add a layer of something over your roots to keep them warm. Leaves grassclippings etc.