It was sposed to hit -10, but did not make it. I slept in my front yard in Claytor. Had a piece of warm window, with a SB on top as an UQ. A thermarest in the pocket of the claytor. Used a 0 degree rectangular down bag from campmor on top with a wool blanket folded around it.
I wore one layer of capilene, fleece gloves, wool socks with fleece socks over, a fleece balaclava, and a fleece muffler. I did stay warm, in fact I was too warm. I woke about 4 AM feeling warm and claustrophobic. I shed the balaclava as well as all the stuff on my head and neck, and tossed and turned a bit. Finally went to the house about 5 AM. Next time I am not going to wear all the stuff around my neck and head. I have a small light wool blanket I will use over my head, won't feel so restrained.
I do know I can definitely take it to -10 with a simple addition of a wool blanket from the stuff I would carry for 20's. I was pleasantly surprised I stayed warm on my underside. I would not want to backpack with the wool blanket though. Paddling would work. May take a very early spring paddle, not worry about cold and snow now. I love the river then.
I learned some things, mainly that I can be out when it is extremely cold and stay warm. Now for those snow shoes and high tec UQ and TQ, backpack. . . . . . and on and on and on the list goes.