I haven't tested this by itself, yet. But, I used this as an overbag with the BA Wind Lip 28 inside of it. It got down into the low 20's, and I was fine. I sleep warm, but I think I could push this combo lower, especially with a bag liner, and/or thermals. Looking forward to testing this bag on it's own in warmer weather.
This review was written in the old system and had content requirements that are different than reviews written today.