First off, this is a fantastic little piece to have, and I highly recommend it for anyone considering it. My first test was in a cave deep in the heart of Kentucky. I specifically to it there to test because it was a consistent 52 degrees Fahrenheit, it was humid, and there was a constant breeze. Getting into the bag, I was immediately very warm, especially in the feet. I got to sleep fairy quickly, and slept soundly for about four hours. I woke up due to a cold spot on the wind side of my bag. I noticed this once again when I woke up in the morning, and attributed it to the zipper being one that side as well, so rearranged the bag so that the zipper was down wind the following night. I woke up again to a cold spot, but this time it was very close to my wake up time, so It didn't bother me. Despite all of this, I really enjoy the bag and plan to purchase another quite soon from the same brand.
This review was written in the old system and had content requirements that are different than reviews written today.