Originally Posted by
ernesthemmingway
Even though that sleep system is rated to -30, you will still need something underneath you, either an underquilt or a thermarest pad, in cold temps. When you lay in the hammock, the sleeping bag underneath you gets compressed, and loses much of its insulating value. I have used this system on ground before with temps in the 20-40 range and definitely needed a pad underneath me.
Also, Ive always doubted that -30 rating. Ive never been that low, but I froze my butt off one night in 18 degrees, and I had a pad underneath me.