I can guarantee you that whether you're comfortable with this pad in winter depends on your body, your gear combo, etc. I personally don't find this warm enough even in fall if I'm using a quilt. Contrary to what the ultralightists will tell you, having sleeping bag under you does help you stay warmer: only a very small portion of your bag is completely compressed indeed your body. I've augmented the warmth of this pad by laying a fleece throw or evazote pad on top of the air pad. In my mind, the air pad is for pressure-point comfort and the other insulation (bag, closed-cell foam pad) are for warmth. For the record, in my Therm-a-rest self-inflating days, it was still recommended to pair with a CCF pad in winter. The summary is that you have to try things out to figure out what works for you. If you have winter camping experience, you'll know how to test the limits; if you don't have that experience, you'll want to test this pad in less risky situations first.