It was cold, no doubt. It didn't matter what kind of rig you were in, on or above the ground.
But I surely have new respect for what a hammock is capable of after seeing Mike and Festus out in those temps.
They both pitched at moderate heights from what I could tell, so given the terrain, and even higher breezes I think they would have been good to go at even colder ambient or windchill temps.
The frozen ground was not compliant at all for me as a ground dweller, and I found myself envious of even a repeatable sleeping position, let alone a comfortable one.
Good stuff, and fun times.