While adding a liner (Big Agnes makes a nice one that attaches inside the bag) can make this a true three-season bag, the Katabatic Gear Palisade 30 is the best and warmest ultralight model we tested for thru-hiking and three-season backpacking. Its warmth-to-weight ratio in exceptional, and it adjusts well to both cold and warm nights. If you're on a tight budget, no model we tested delivers more warmth and versatility for the price than the Enlightened Equipment Revelation 20.
The Pitchpine UL 45 has been discontinued. To see more options, check out our complete Ultralight Sleeping Bag Review.