Reviews You Can Rely On

Western Mountaineering UltraLite Review

Our favorite premium backpacking bag to keep us warm at night when the temperature drops
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western mountaineering ultralite backpacking sleeping bag review
Credit: Ian McEleney
Price:  $620 List
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Manufacturer:   Western Mountaineering
By Jack Cramer and Ian McEleney  ⋅  Nov 22, 2023
81
OVERALL
SCORE


RANKED
#2 of 15
  • Warmth - 25% 10.0
  • Weight - 25% 7.3
  • Comfort - 20% 7.0
  • Packed Size - 15% 7.0
  • Features - 15% 9.0

Our Verdict

The Western Mountaineering UltraLite is our pick if you're planning to be in colder 3-season conditions. Until we tried this bag, it was hard to imagine that one sleeping bag could be both warm enough for winter and cool enough for summer. The UltraLite pulls this off with 17 ounces of down and a continuous horizontal baffle design that lets you move those feathers to the underside of the bag to vent excess heat on warmer nights. To enjoy this impressive versatility, you have to fork over some serious cash, and there are mild drawbacks in weight and packed size. However, in the hands of an experienced backcountry traveler, this bag's usefulness extends throughout the calendar year. See it rated versus top competitors in our review of the best backpacking sleeping bags.
REASONS TO BUY
Best-in-class warmth
Legit draft collar
Lightweight
Exceptional loft
REASONS TO AVOID
Really pricey
Kind of bulky
Awkward hood closure
Editor's Note: We updated this review on November 22, 2023, after retesting this sleeping bag against some new additions.

Compare to Similar Products

 
Awards Top Pick Award Editors' Choice Award Top Pick Award Best Buy Award Best Buy Award 
Price $600.00 at Backcountry
Compare at 2 sellers
$555.00 at Backcountry
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$549 List
$549.00 at Feathered Friends
$285 List
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$100 List
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Overall Score Sort Icon
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Star Rating
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Bottom Line The best bag for the coldest shoulder season nightsIf we could only have one bag for the rest of our lives, this would be itThe ideal bag when you need the warmth, but ounces matter tooThis inexpensive model has decent warmth for the weight, and features that are well thought outThis bag is comfortable and has decent features - pair this with a bargain price and it's a great deal
Rating Categories Western Mountaineer... Western Mountaineer... Feathered Friends H... Mountain Hardwear B... REI Co-op Trailmade 20
Warmth (25%)
10.0
8.0
8.0
8.5
6.5
Weight (25%)
7.3
8.0
8.4
6.3
4.4
Comfort (20%)
7.0
9.0
6.0
7.0
6.5
Packed Size (15%)
7.0
8.0
8.0
5.0
3.0
Features (15%)
9.0
8.0
9.0
6.5
7.0
Specs Western Mountaineer... Western Mountaineer... Feathered Friends H... Mountain Hardwear B... REI Co-op Trailmade 20
EN Temp Rating (Lower Limit) 14°F 21°F 30°F (not EN rated) 15°F 21°F
Insulation 850+ FP Down 850+ FP Down 950+ FP Down 650 FP Duck Down Synthetic - recycled polyester
Measured Weight 1.8 lbs 1.5 lbs 1.3 lbs 2.3 lbs 3.2 lbs
Compression/Stuff Sack Weight 1.0 oz 1.0 oz 1.0 oz 1.9 oz 1.6 oz
Fill Weight 17.0 oz 13.0 oz 12.0 oz 21.0 oz 34.9 oz
Shell Material 12D Extremelite 12D Extremelite 10D Pertex Endurance 20D ripstop nylon Recycled polyester
Liner Material 12D nylon taffeta 12D nylon taffeta 15D ripstop nylon 30D nylon Polyester
Hydrophobic Down? No No No No N/A
Neck Baffle? Yes No No Yes No
Small Organization Pocket? No No No Yes Yes
DWR Treatment? Yes Yes No No Yes
Zipper Info Full-length / side Full-length / side Full-length / side Full-length / left Full-length / left
Shoulder Girth 59 in 64 in 58 in 62 in 62 in
Hip Girth 51 in 56 in 52 in 53 in 58 in
Foot Girth 38 in 39 in 38 in Not listed 40 in
Compression or Stuff Sack? Stuff sack Stuff sack Stuff sack Stuff sack Stuff sack

Our Analysis and Test Results

If your budget lets you shop for the absolute best backpacking sleeping bag, you will likely end up with a choice between Western Mountaineering and Feathered Friends bags. These boutique firms make some of the highest quality down products on the continent. You pretty much can't go wrong either way. But to help you out a little, the UltraLite sets itself apart with a legit draft collar that ensures you can seal all your body heat in on colder nights.

Performance Comparison


western mountaineering ultralite backpacking sleeping bag review - the ultralite came close to winning our editors' choice but the...
The UltraLite came close to winning our Editors' Choice but the review team ultimately decided that it's probably too warm for most 3-season users. However, it still earns accolades as the best cold weather 3-season bag.
Credit: Jack Cramer

Warmth


While it's not advertised on the Western Mountaineering website, this bag does get an EN Temperature Rating. It has a Comfort rating of 25°F and a Limit rating of 14°F. Our testers believe the UltraLite is one of the warmest 3-season bags we have tested. Its 17 ounces of 850+ fill power down seems to supply more warmth than the other 20°F models in our review.


This superior performance is partly due to the substantial draft collar on the UltraLite. Not only does the collar keep drafts out, but it also holds heat in. When the cold creeps in, the collar can be cinched closed with the internal drawstring, and it's effective at sealing heat inside the main compartment of the bag. Because the drawcord is stretchy, we didn't find it to be overly restrictive. Some testers, however, consider the same collar to be unnecessary weight for most 3-season temperatures. Maybe so. But in colder spring and fall conditions or at high altitudes, you won't have to worry about staying warm with this bag. The inclusion of the draft collar also arguably extends the UltraLite's usefulness to mild winter applications — depending on your layering choices, shelter, and the rest of your sleep system.

The horizontal baffle construction means that its down insulation is sewn into fabric tubes, or baffles, that are perpendicular to the length of the bag. These baffles are continuous, which allows you to shift the insulation to the top or underside of the bag, depending on conditions. On colder nights, moving more feathers above your body will ensure more heat is trapped inside. In warm conditions, do the opposite and shift feathers below your body to allow excess heat to escape. You don't have the same option with vertical baffles or synthetic insulation.

western mountaineering ultralite backpacking sleeping bag review - the draft collar uses a stretchy cord for adjustment. this lets you...
The draft collar uses a stretchy cord for adjustment. This lets you fine tune the fit, and the stretchiness makes it more comfortable.
Credit: Ian McEleney

Weight


Despite providing best-in-class warmth, this bag weighs in at an impressive 1.8 pounds in the 6' 0" length. Although this is near the middle of our total field of sleeping bags, it compares favorably with bags that provide similarly high insulation levels.


For cold nights, we consider the extra ounces of the UltraLite to be well worth the weight. Its overall warmth-to-weight ratio is also among the highest we've seen. The weight of this bag should not dissuade anyone from purchasing it.

western mountaineering ultralite backpacking sleeping bag review - very light 12 denier fabric inside and out is one of the properties...
Very light 12 denier fabric inside and out is one of the properties that keeps this bag light despite its warmth.
Credit: Ian McEleney

Comfort


Unfortunately, the UltraLite does not offer quite the same comfort as its outstanding Western Mountaineering relatives. Sure, it can boast the same cozy down and soft ExtremeLite fabric, but its somewhat narrower dimensions don't provide the same spacious comfort.


These dimensions, however, are similar to most of the other standard mummy bags we tried. The UltraLite would thus earn an average comfort score were it not for its gentle, cloud-like loft that caused us to give it an extra point. We think that most backpackers will find it to be reasonably comfortable.

western mountaineering ultralite backpacking sleeping bag review - the awesome loft and soft fabric of the ultralite boost its overall...
The awesome loft and soft fabric of the UltraLite boost its overall comfort.
Credit: Jack Cramer

Packed Size


A common consequence of lots of warm insulation is a larger packed size. The UltraLite is no exception. Using an aftermarket compression sack, we were able to squeeze this bag down to 9 liters in total volume.


Shoppers should keep in mind, however, that per liter of pack space, this bag offers unrivaled warmth. Moreover, the difference between the biggest and smallest bags in this review was not especially large. When compared to more distant competitors, the UltraLite is relatively small. Like with weight, we don't think packed size should be anyone's reason to avoid purchasing this high-quality bag.

western mountaineering ultralite backpacking sleeping bag review - the ultralite stuffed into its supplied sack. if you want to make it...
The UltraLite stuffed into its supplied sack. If you want to make it smaller, we recommend purchasing a dedicated compression sack.
Credit: Ian McEleney

Features


Although the UltraLite lacks many of the fancier features of other bags, simpler is sometimes better. The absence of an organizational pocket or additional venting zippers was noted (and sometimes missed), but it helps this bag save weight and space in a pack.


Meanwhile, the only arguably unnecessary feature, a functional draft collar, is the defining characteristic that sets the UltraLite apart from its closest competitors in terms of warmth and versatility. Thus, when you consider both the features this bag does and does not have, its overall design makes more and more sense.

western mountaineering ultralite backpacking sleeping bag review - the velcro tabs used to seal the hood and draft collar are slightly...
The velcro tabs used to seal the hood and draft collar are slightly awkward to use and not great at keeping things closed.
Credit: Jack Cramer

Of the few features this simple bag does sport, the long zipper is one of the most useful. It let our testers put some targeted ventilation on sweaty, stinky, or damp feet without allowing too much cold air into the bag. It also allows you to open the bag up all the way.

western mountaineering ultralite backpacking sleeping bag review - one benefit of the long zipper is easy ventilation of the lower bag.
One benefit of the long zipper is easy ventilation of the lower bag.
Credit: Ian McEleney

Should You Buy the Western Mountaineering UltraLite?


If you are the kind of backpacker who likes to keep their pack light and their gear closet uncluttered, the UltraLite could be a great choice. Because this bag is warmer than the competition, it can be more comfortably used later in the fall and earlier in the spring. For folks who like to get out all year, this bag and a zero-degree bag could cover you. While it's far from cheap, we believe the UltraLite is actually a great value when you factor in the weight and performance benefits you get to enjoy over its 10+ year lifespan.

western mountaineering ultralite backpacking sleeping bag review - the ultralite may be too warm for hot summer nights but it's awesome...
The UltraLite may be too warm for hot summer nights but it's awesome for cold desert bivies.
Credit: Jack Cramer

What Other Backpacking Sleeping Bags Should You Consider?


While the UltraLite is a fantastic sleeping bag, not all backpackers need the extra warmth. For those looking for a high-performing bag who don't venture out much beyond summer — or who won't be in higher and colder places — the Feathered Friends Hummingbird UL 30 provides all the same features but isn't quite as warm. The benefit of this trade-off is that it's lighter and takes up a bit less space in your pack. Readers who balk at the price tag of the UltraLite might want to click over to the REI Co-op Trailmade 20. It has a decent feature set and a shockingly low price tag. Backpackers who also camp out in the front country could even find that the Trailmade and UltraLite together make a great quiver.

Jack Cramer and Ian McEleney