26 degrees.

END OF REPLY

I _really_ would like to have added: F.

For others: This was a Neo large. Reference point: I am a cold sleeper (for WM bags, for example, I need a 10 degree margin above their rating). This is lowest temperature I've experienced without having brought along an insulating pad, so I really don't know what the lower limit is of the Neo alone. But it's clearly lower than that, for me, because I was a little under-bagged on that trip (a sleeping bag I rarely push down past 30 F) and was still comfortable. With a more suitable bag I'm sure I had another 5-10 degrees on the Neo.