Just got back from a 3 day backpack in the Ohlone Wilderness Area near Freemont California. I was using a regular Neoair in an old Walrus Zoid 1 tent with an REI Sub Kilo 20 degree bag. Almost too warm on top, but a little cool underneath. Not enough to keep me awake, but noticeable. My friend had a short Neoair and he experienced the same thing. I was a little disappointed because the low air temp was only about 35 degrees. My theory was that the ground was still cold from a recent cold spell here in Northern California. Doing another backpack at Point Reyes Jan 18th. I'm going to cut up an old yoga mat to put under the torso area and see how that works. Maybe a blue pad would be better, but I don't have one of those. I hate to carry the extra weight, but it's better than being cold.

That's about what I expected. I certainly wouldn't have thought the Neoair would go below 30 without extra padding.

I have a short NeoAir which I used at Lake Elanor in northern Yosemite on the weekend in October when the Sierra had an early snow. I also used a Gossamer Gear Thinlite insulation pad under the NeoAir. The Thinlite pad is 1/8 inch thick, weighs all of 2 oz, and costs $10. It gave me 2 advantages- 1- the NeoAir did not slip around on my tent floor, 2- it added insulation from the ground. That night we had snow/hail of about 1/4 inch on the ground. Outside temps were in the middle 30's, (I had a recording max/min thermometer) the Neoair did fine with the Thinlite pad under. I don't know how well the NeoAir would have done at much lower temps, but I was comfy into the mid 30's. My sleeping bag is an older version of the WM Ultralite (25 degree version). I did have on a wool top and capalene bottoms.

I used my small NeoAir in early Oct. past New Army Pass at Sky Blue Lake and beyond. Temps were 5 and 4, very high winds, snow threatening, no extra pad underneath, slept warm in my WM Apache, 15 bag. Of course, the ground was not frozen yet.