A 15° or 20°F bag suffices for most three-season trips. Down is a highly compressible insulation and provides more warmth for its weight than synthetic fills, which are preferable for use in wet conditions. Look for a zipper draft tube, a draft collar, and a trim-fitting design for maximum heat-trapping efficiency. Condensation will dry faster on a dark-colored shell.
Adjust the temperature rating up or down if you’re
a very cold or warm sleeper, or if your typical hike exposes you to sweltering desert temperatures or frigid mountain air. Some companies make bags specially shaped to fit the female form.
|Summer/ desert||40°F||Brushed or fleece lining for no-stick comfort, minimal features (hood and draft collar optional), wraparound zipper to open for blanket use
|Rainforest||–||Synthetic fill, water-resistant shell|
|Winter||0°F||Adjustable draft collar, contoured hood, 6″ of extra length for storing water bottles, clothes, and cold-sensitive gear
|High mountain/ arctic||-20°F or lower||Down fill for compressibility, extra length
for water-bottle storage, extra girth (optional) for layering
|Snow cave/ tentless||–||Water-resistant/windproof shell or bivy sack|
|For This Sleep Style||Look For
|Thrasher||Elastic seams (for stretch), semirectangular shape or big-guy girth (for more space), or expansion panels (for adjustable space)|
|Snuggler||Mating zippers on same-length bags so you can cozy up with a significant other|
|Perspirer||Brushed or fleece lining (or bag liner), synthetic fill, breathable shell (no laminates or special coatings), two-way zipper|