Best sleeping bags for three-season camping
The temperature on the label is usually not the temperature you can sleep at. What the ratings mean and how to read them.
4 products ranked Updated
Our rankings are built from published testing by named outlets, not from our own lab. We earn a commission when you buy through our links, and it never changes the order.
The short answer
- 1 Exped Terra 15 Best value $259.95
- 2 Western Mountaineering MegaLite Best overall $630, per OutdoorGearLab
- 3 Marmot Trestles Elite Eco 20 Best for damp climates $189.00
- 4 REI Co-op Trailmade 25 Cheapest worth carrying $129, per OutdoorGearLab
Prices checked 9 September 2026. They move constantly — the retailer's own page is the authority.
Exped Terra 15
4 / 5
Our reading of OutdoorGearLab — 78/100 and a Best Buy , 2026
A 12F ISO rating for $260 is the best value in the test by a distance — the bags scoring six points higher cost more than twice as much. The compromise is fill power: 650 duck down rather than 850 goose, which as the section above explains costs you weight rather than warmth. At 2.8 lb it is heavier than the premium bags and just as warm.
Pros
- Best Buy at 78/100, six points off the top score
- 12F ISO — a genuine standard rating, not a marketing number
- Less than half the price of the Editors' Choice
Cons
- 2.8 lb, twice the weight of the lightest bags here
- 650 fill power means more bulk in the pack
Where these findings come from
- OutdoorGearLab: 78/100 and a Best Buy; 12F ISO rating, 650+ fill-power duck down, 2.8 lb, $260
Western Mountaineering MegaLite
4.5 / 5
Our reading of OutdoorGearLab — Editors' Choice at 84/100 , 2026
Joint-highest score of 17, and 1.5 lb for a 22F bag is exceptional — that is less than the Exped above while being rated for similar conditions. This is what 850-fill goose down buys: the same warmth in half the bulk. At $630 it is a purchase for people who carry a pack often enough to feel the difference.
Pros
- Joint-highest score of 17 bags
- 1.5 lb at a 22F rating
- 850+ fill power packs down far smaller
Cons
- $630
- Down collapses when wet — see the synthetic pick below
- No image and an unverified price
Where these findings come from
- OutdoorGearLab: Editors' Choice, 84/100; 22F rating, 850+ fill-power goose down, 1.5 lb, $630
Marmot Trestles Elite Eco 20
3.5 / 5
Our reading of OutdoorGearLab — 66/100 , 2026
The lowest score here and the right bag for a lot of people, which is the sort of tension a single ranking hides. The section above argues that in a damp climate the down-versus-synthetic question is not close: down loses most of its warmth wet, synthetic keeps working. This is the only synthetic bag in our four, it holds a 12F ISO rating, and it costs $189. It also weighs 3.7 lb, which is why it scores 66.
Pros
- Synthetic fill keeps insulating when damp
- 12F ISO at $189
Cons
- 3.7 lb — the heaviest bag here by a pound
- 66/100, the lowest score of our four
Where these findings come from
- OutdoorGearLab: 66/100; 12F ISO rating, synthetic fill, 3.7 lb, $189
REI Co-op Trailmade 25
3 / 5
Our reading of OutdoorGearLab — 62/100 and a Best Buy , 2026
$129 for a 20F ISO synthetic bag at 3.0 lb. It is the lowest-scoring pick here and it is a real, standard-rated bag rather than a sack of wadding with an optimistic number on it — which is what most bags at this price are. For a few weekends a year in a temperate climate, this is enough.
Pros
- A genuine 20F ISO rating at $129
- Lighter than the Marmot despite also being synthetic
Cons
- Lowest score of the four
- A 20F rating is the limit of three-season use
- No image and an unverified price
Where these findings come from
- OutdoorGearLab: 62/100 and a Best Buy; 20F ISO rating, synthetic fill, 3.0 lb, $129
What actually matters
Comfort rating, not limit rating. European standard testing produces several numbers. The comfort rating is the temperature a cold sleeper can sleep at; the limit rating is where a warm sleeper is curled up and just about surviving. Marketing tends to quote the limit. Buy on comfort.
Down or synthetic, decided by damp. Down is lighter and packs smaller for the same warmth, and loses most of it when wet. Synthetic is bulkier and keeps working damp. If your camping involves British weather, that is not a close call.
Fill power is about weight, not warmth. A higher fill power means the same warmth for less weight, not more warmth. A 600-fill bag and an 850-fill bag can be equally warm; one is heavier.
Shape. A mummy bag is warmer for its weight because there is less air to heat. It is also more restrictive, and a bad night's sleep is a real cost.
Where this comes from
We do not test sleeping bags. Our source tested 17 in the field and the lab, from California's Sierra Nevada to Wyoming's Wind River Range to Zion and Death Valley, with nighttime lows from 10F to 70F and elevations from below sea level to 14,000 feet.
Crucially for this guide, they publish which standard each temperature rating comes from — ISO or EN — rather than reprinting whatever number the maker put on the stuff sack. The section above explains why that matters more than the number itself.
Two picks have no photograph
Western Mountaineering's site carries images only of a different bag in its range, and REI's store refuses us even in an ordinary browser. So those two picks carry an Amazon search link and a price quoted from our source and dated. We would rather show fewer pictures than the wrong bag.
What we are leaving out
Bags rated below about -5C comfort, which are winter equipment, and anything without a published standard rating.
Where this comes from
We did not test these. These people did.
Every score on this page rests on the testing below. The ranking is ours; the measurements are not. How we research.
- OutdoorGearLab — 17 bags, field and lab, across the Sierra Nevada, Wind River Range, Zion and Death Valley, with lows from 10F to 70F. Publishes which standard (ISO or EN) each temperature rating comes from.
Questions people ask
What temperature rating do I need?
Does a sleeping mat matter as much as the bag?
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