Friday night I strung up my NX250 in the back yard for a "Winter Conditions" test since it was supposed to get down to 30F. It got down to about 24F, with 26 mph wind and granular snow falling nearly sideways.
I used a Speer Snugfit velcro-type underquilt which matches up with the velcro on the hammock perfectly. No other insulation was used and I zipped up in a mummy bag with only a t-shirt, shorts and no socks. The weather shield was kept closed, and I was perfectly warm all night.
Throughout the night the hammock swung back and forth in the wind, but this was not disturbing at all. Toward morning it was a bit "cool" in the foot-area, but not enough to keep me awake.
If I had put on some socks and maybe long underwear of some type the situation would have been perfect, although it was very good without these things.
When heading out to the woods this November, I will definately take along some major socks and longjohns, but this test put my mind at ease. The NX250 is without question a 4-season outfit.