I purchased this bag for a trip this spring. The first night was a little on the warm side and it worked perfectly. The second night was about 40 deg F but I froze. I had the Therm-A-Rest Trail Pro with an R-Value of 4.8 and wore 3 pairs of wool socks, warm synthetic long johns, a base layer, 2 mid layers with a hood, my rain jacket, gloves, neck gaiter, and headband ear warmer to finally get warm enough to fitfully sleep. This seems excessive in a bag rated to 20 F bag, 34 F comfort. Unfortunately I have to return it.