User Review: The North Face Dark Star -40
Temperature Rating: -40 fahrenheit
Weight: 5.5 pounds
Price Paid: $125
i purchased this as a dedicated cold weather bag (it was purchased used - the prior owner used it for one season). i winter hike in the white mountains, and a zero degree-rated bag was inadequate unless i used it with a liner and a bivouac bag.
i slept in this bag in temperatures down to -20 fahrenheit this winter. because i had no experience with the bag, i also used a liner to add some warmth. i ended up shedding the liner and almost all my clothes. i don't know if the bag is as warm as its -40 degree rating, but it was more than enough for -20.
the bag has synthetic fill which is thick and feels bulky. i prefer synthetic fill because it does a better job dealing with moisture evaporation in very cold weather, but this bag is nearly six pounds in the long version - much heavier than a comparable down bag. it has a good draft tube next to the zipper, and double draft tubes at the opening, with a well-shaped hood. the hood and opening pull tight with shock cord and toggles which are a little complicated to work with. it would be a good idea to play with them and figure out how they work before you try to adjust in the dark. the bag is roomy - plenty of room for inner boots and other gear you may want to sleep with and dry out.
some nice features - a glow-in-the-dark zipper pull; a small zippered pocket for essential items, eg a small flashlight, near the top of the bag; and velcro flaps near the zipper that help fully seal the opening against the cold.
my only gripe with this bag is fitting it into my pack. even with a good compression stuff sack, this sleeping bag is comparable to a medicine ball. down bags are much better in this regard. i didn't enjoy cramming the bag into my pack, but i most certainly appreciated the warmth, the good design, and the very good workmanship.
words to the wise - do not store this or any other synthetic bag in a compression stuff sack or any other bag that limits the loft, because it could reduce the warmth of the the bag.