I live in northern Greenland, and we like staying…
Fill: 900 fill down
Temperature Rating: -18 degrees celcius or 0 Fahenheit
Weight: 2 lbs 8 oz
I live in northern Greenland, and we like staying in tents in the winter season where we go dogsledging. I have tested it several times in temperatures down to -20 degrees and I kept perfectly warm with only long woollen underwear underneath.
The reason why I only rate it with 4 stars is due to the fact that its shell isn't water-resistant. Sleeping in tents in this kind of cold weather makes the condensed water freeze before it is led out of the tent, and the sleeping bag gets a little moist on the outside. With no chance of drying during daytime I don't know whether it will affect its abilities.
However - it's a great bag in soft material who very fast warms you up, and the packing size gives extra important space in your backpack.