User Review: REI Men's Zephyr +15
Temperature Rating: 15 F (more like 45-50)
Price Paid: $139
This might keep you warm in 45 degrees. If you add a fleece liner to it, it might work in 35. The only way I can stay warm with this in anything close to 15 degrees is to put another sleeping bag over it. I was freezing in Yellowstone when the temperature dipped below 25 degrees. I was freezing in Canada when the temperature dipped below 30 and was cold in Mississippi when the temperature was under 40. This might be a 15 degree bag if you sleep really, really, really warm or wear a lot of clothes when you sleep.