Verdict
Head-to-head · Best 0 Degree Sleeping Bags

Sea to Summit Spark 0F vs Western Mountaineering Kodiak MF

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

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The short answer

Western Mountaineering Kodiak MF comes out ahead by a narrow margin (4.5 vs 4.4). Western Mountaineering Kodiak MF is best for: Cold-weather campers and side sleepers who want the most reliable 0°F warmth and room to move, and don't mind paying a premium. Read the strengths below before deciding.

Sea to Summit Spark 0F
Ranked #3 in Best 0 Degree Sleeping Bags
Sea to Summit Spark 0F
2 sourcesall derived$999as of Oct 11

The Spark 0F is the ultralight of this group, packing a genuine 0°F-rated bag into about 2 lb 7 oz and a sub-10-liter stuff size. It uses 850+ fill Ultra-Dry down, and reviewers find its temperature rating accurate. Against that: a snug, less-forgiving cut, a thin shell offering little wet-weather protection, and a steep price for the warmth.

Strengths
  • — Among the lightest 0°F down bags at roughly 2 lb 7 oz
  • — Sub-10-liter packed size, the most compressible bag here
  • — 850+ fill power Ultra-Dry treated goose down resists moisture
Watch-outs
  • — Snug ultralight cut is less forgiving than the Kodiak or Ibis
  • — Thin shell offers little wet-weather protection
  • — Pricey at roughly $649-$679 for the warmth delivered
Western Mountaineering Kodiak MF
Higher ratedRanked #4 in Best 0 Degree Sleeping Bags
Western Mountaineering Kodiak MF
1 source$795as of Oct 10

OutdoorGearLab consistently names it their top winter pick and found it performed more like a -20°F bag than a 0°F one. The trade-off is a list price near $900 and a wide cut that costs some warmth-to-weight efficiency against narrower mummies.

Strengths
  • — Tested warmer than its 0°F rating; held testers to roughly -10°F with light layering
  • — 1.88 lb of 850+ fill goose down with continuous baffles you can shift top-to-bottom
  • — Wide-cut mummy with generous shoulder, hip and footbox room for side sleepers
Watch-outs
  • — List price near $895-$950 is among the highest in the category
  • — Wide cut adds dead air space, so it is not the most weight-efficient 0°F option

Derived means the reviewer published no score, so one was inferred from their written verdict. Everything else is a number the publisher printed. How we rank.

How they stack up

Sea to Summit Spark 0F

One of the lightest and most compressible bags here, undercutting the Therm-a-Rest Parsec 0F on packed size and far lighter than the Western Mountaineering Kodiak MF, Feathered Friends Ibis ES 0 and Mountain Hardwear Phantom 0, but with a snugger cut and a thin, less weatherproof shell.

Western Mountaineering Kodiak MF

The roomiest and warmest bag here, beating the Mountain Hardwear Phantom 0 and Therm-a-Rest Parsec 0F on real-world warmth and the Feathered Friends Ibis ES 0 on cut width, but it is heavier and pricier than the lighter Sea to Summit Spark 0F.

Specs side-by-side

SpecSea to Summit Spark 0FWestern Mountaineering Kodiak MF
Temperature Rating0°F limit / 14°F comfort0°F (-18°C)
Fill Power850+ Ultra-Dry goose down850+ goose down
Fill Weight29.6 oz (840 g)1.88 lb (30 oz)
Total Weight2 lb 7 oz (1113 g)2 lb 12 oz
Packed Size9.9 L—
ShellUltralight nylon20D MicroLite XP nylon
ZipperFull-length YKK with draft tube—
CutSnug ultralight mummyWide mummy, continuous baffles
MaterialNylongoose-down
Dimensions83.1"L x 52.8"W—
Warranty—Lifetime craftsmanship
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