Without acclimatization is an interesting variable to throw in the equation.
With acclimatization here's an instance of
Dendrobium nobile subjected to 26F for several hours and here's a
Dendrobium nobile that's experimentally being grown outdoors year around in Ireland.
Without acclimatization is anybody's guess but if
kept on the dry side I would be surprised if your nobile had problems tolerating temperatures just above freezing. Not sure when that occurs in your area.