Whether your travels are taking you to Kilimanjaro or Mount Kenya, to Everest Base Camp or backpacking during the colder months, a good winter sleeping bag is essential.
Hiking at in the cold or at altitude is hard and after a strenuous day on the trail, getting a good night’s sleep is hard enough, without being cold as well!
We've checked out 12 winter sleeping bags for you to consider for your next mountain adventure.
Winter sleeping bags divide into 0F (-15C) and 15F (-10C) temperature ratings. For super-cold weather, or hiking that involves going over 10,000ft, you'll probably want to go with a 0F bag.
0F (-15C) Down Sleeping Bags
These are the warmest sleeping bags for their weight but they are the most expensive. You might want to choose one of these if you tend to feel the cold at night and are planning more than just a “one-off” expedition.
Thanks to their superior warmth-to-weight ratio, these are the best sleeping bags if you are planning an unsupported backpacking trek. For sleeping in Kilimanjaro’s crater (Crater Camp) I would highly recommend a 0F rated Down sleeping bag as it’s bone-chillingly cold next to the glacier.
Top Choice: RAB Expedition 100 (this wins on warmth)
Best for Budget: Kelty Cosmic Down
OF (15C) Synthetic Sleeping Bags
Synthetic sleeping bags have come a long way since the old bulky, heavy rectangular offerings. If you have an allergy to Down, or simply don’t want to spend the money, then check out these synthetic winter sleeping bags.
Synthetic sleeping bags generally pack a bit bigger than their down counterparts, and weigh a bit more. This is of little concern unless you are planning an unsupported multi-day backpacking trip.
Another advantage of synthetic over down is that it dries a lot quicker and is much more forgiving in wet conditions.
Top Pick: Hyperlamina Torch 0
Best for Budget: Mountain Hardwear Hotbed (not as low-cost but much better value than the Coleman)
15F (-10C) Down Sleeping Bags
It’s perfectly possible to have a comfortable night’s sleep with a good 15F rated sleeping bag. For most winter backpacking at home, this should be sufficient.
Depending on where you are going, if your trek has you sleeping in lodges (Everest Base Camp) or huts (Marangu Route, Kilimanjaro) then you might not necessarily need the 0F rated bag. This is entirely a personal choice.
If you tend to sleep “cold” at home, when you are not exhausted from 7 hours on the trail then I would suggest you opt for the warmer bag, rated 0F.
If you do decide to take the 15F rated sleeping bag, then I highly recommend a good sleeping bag liner if you are headed to higher elevations, where the nights are bitterly cold and the altitude is affecting you.
When choosing whether to take a 15F bag, do bear in mind that altitude and exertion can both conspire to make you much colder than you would be normally.
Note: if you plan to camp at Crater Camp, Kilimanjaro – I highly recommend a 0F rated bag.
Top Pick: RAB Ascent 700
Best for Budget: Outdoor Vitals Atlas
15F (-10C) Synthetic Sleeping Bags
Slightly heavier and bulkier than their down counterparts, synthetic sleeping bags are an excellent choice for those allergic to down or for travels in wet conditions.
Synthetic sleeping bags perform much better than down when they get wet and are less expensive. For supported treks, when space and weight is not crucial, then a synthetic sleeping bag is an excellent choice.
If space and weight is at a premium, then down will out-perform synthetic insulation every time.
Top Pick: Mountain Hardwear Lamina Z
Best for Budget: Coleman North Rim (do me a favor, only buy this one if you are on a serious budget and cannot afford anything better. It'll do, but only just!)
Choosing Winter Sleeping Bags
"Seasons" & Temperature Rating
Most sleeping bags will have a temperature (warmth rating) often using the “European Norm” system. Additionally they are divided into “Seasons”:
The 1 and 2 season sleeping bags don’t leave much room for error. Even in the summer if you have a cold snap or start feeling somewhat under the weather, these can be left lacking quickly.
The most versatile sleeping bag for most backpacking/camping excursions would be the three season bag. If it’s hot, you can unzip it but it’s got the capacity to keep you warm if the temperature drops.
Even during the summer, if you intend to sleep above 10,000ft you’ll need a winter sleeping bag. All multi-day hikes at altitude mean freezing cold nights. Additionally, the more fatigued you get, the colder you will feel.
I recommend a winter sleeping bag with a temperature rating of 0F (-15C) or 15F (-10C).
However, with a sleeping bag rated 15F (-10C) it is advisable to take a good sleeping bag liner, to keep you comfortable on freezing mountain nights.
A Note About EN Ratings
Note that warmth ratings are not to be relied on exclusively. The EN ratings (European Norm) are often inaccurate. The reason is that they are based on what the “average” person finds comfortable or otherwise.
They are an attempt to standardise the conversion from an insulation value to a temperature range. But they do not take into account that there are many variables that contribute to how comfortable someone is when camping.
- as with most things, you get what you pay for. That’s not to say that the most expensive winter sleeping bag is necessarily the warmest.
How the EN System Works
Don’t rely on it, especially in the “extreme” cases. Use it as a guide only.
The three “standard” ranges are:
You may see an “Upper Limit” rating - this refers to the temperature that an “average” man can sleep without sweating too much. A pretty useless piece of information in my opinion.
The problem with these temperature ratings, apart from the definitions involved in “standard”/”average” people, is that they also take no account of any other factors in your sleep system.
Apart from the fact that people feel the cold differently, the outside conditions: wind, humidity also play a part, as well as the fit of your sleeping bag and whether you are using a sleeping pad are all factors in how well your sleeping bag will perform.
Overall, I take these ratings with a pinch of salt. Always prepare for colder temperatures than you are expecting. It’s easier to peel off and unzip the bag if you are a bit hot, but getting caught on a very cold night can be serious.
Most winter sleeping bags will state that they are 15F or 0F - although as we’ve seen, there are a number of variations within these ratings.
Whether you choose to buy a 15F or a 0F will depend on (a) your budget (b) your expectation of future usage (c) how cold or warm you tend to be at night.
If you are planning multiple treks at altitude, you may like to consider a 0F, but if it’s a one-off trip to Everest Base Camp or Kilimanjaro, then you could easily get away with a 15F.
Shape, Style & Size
Most modern winter sleeping bags are a “Mummy” shape - looking a little bit like a sarcophagus. This design traps the heat next to your body, minimizing heat loss from the bag so that you stay warmer through the night.
This shape also means the bag is less bulky for fitting into your duffel bag or backpack without compromising on warmth.
Mummy-style sleeping bags have a hood that can be secured around your head and a neck collar that prevents heat loss from your head and neck area.
The narrower the hip/shoulder specifications, the more heat is retained in the sleeping bag. This can be at the expense of comfort, as you may not like the feeling of being restricted.
If you are a restless sleeper, or like to sleep wearing a few layers, opting for a slightly larger (therefore slightly less thermally efficient) bag may keep you more comfortable through the night.
You want to make sure that the sleeping bag you choose will actually fit. If you are 6’5” you don’t want to be buying a petite sleeping bag.
Most high-end bags will come in a couple of different lengths, so if you are on the tall side, or want room in the footbox for a hot water bottle, be sure to size up.
Be aware that larger sizes (obviously) add weight and volume, an important consideration when backpacking.
Women’s specific bags are often a slightly different cut from men’s/unisex, and sometimes have more insulation in targeted areas such as footbox and core. The colors make an attempt at being more girly, but overall, I haven't found much difference in terms of performance.
Winter sleeping bags use either down (duck/goose) or synthetic insulation, some a combination of the two.
Down filled bags are significantly more expensive, they hate getting wet and dry slowly. However, they have an extremely good warmth-to-weight ratio keeping you very warm on cold mountain nights.
Down also compresses very small and is super-light, minimizing the amount of weight and space taken up in your backpack.
If you are going on an unsupported backpacking trip where space and weight is at a premium, then Down fill is superior to synthetic.
Goose down is superior to Duck down in terms of its compressibility and warmth-to-weight ratio, though for most of us, we won't notice the difference between a premium quality duck-down sleeping bag and one filled with goose down.
For down sleeping bags, “fill power” is the amount of loft - or volume - any given weight of down produces. So an ounce of 800 fill down will produce more loft (more trapped air - and more warmth) than an ounce of 600 fill down.
The lower the fill power, the more weight is required to produce similar amounts of warmth.
Hydrophobic down: down that is treated with a polymer to make it somewhat water resistant. Hydrophobic down is not waterproof, but it dries quicker and the feathers don’t clump together so quickly. For the tiny bit of extra weight it adds, it is well worth it.
Synthetic filled bags are bulkier as they doesn’t compress as much, and can be heavier. However they are cheaper, better for wet conditions, maintaining their thermal efficiency and drying quickly. This gives you the peace of mind that you’ll still be warm even if it does get wet.
Often recommended for the treks that require camping, such as Kilimanjaro (except Marangu route), Mt Kenya, and the Annapurna circuits, as there is more risk of getting wet, and often on these treks, someone else is carrying your gear.
All that being said, I always use a down winter sleeping bag, even when camping! On camping trips I just be very sure to keep it well stowed in a waterproof stuff-sack. And I avoid sleeping in leaky tents.
Weight & Compressibility
A major consideration is always going to be weight and compressibility. If you are carrying your own gear, you’ll want a sleeping bag that packs down into the smallest size possible and weighs as little as possible.
If you are on a supported trek and have porters or yaks carrying your kit then you can afford to be less concerned with weight.
Down comes up trumps in both the weight and the compressibility stakes. Quite apart from being the warmest - it’s warmth to weight and warmth-to-volume ratio is unsurpassed.
The cut of the sleeping bag can also have an effect on it’s compressibility, the mummy shaped bags with their tapered cut tend to compress down smaller than the rectangular ones.
Tip: if your bag doesn’t come with a compression sack, then get yourself a good waterproof one. It will keep the bag dry in your backpack and compress it as small as possible.
The shell material fabric will contribute to the overall weight, and this will be a trade off between weight and durability.
If you want it all - you want a down sleeping bag!
Weather Resistance and Durability
Whilst the bag won’t be waterproof, it’s important that it can withstand a bit of condensation - at the very least. A decent shell fabric with a DWR treatment should be adequate for all but the worst of leaking tents and downpours.
The more robust the shell material, the heavier it’s likely to be. These days it’s possible to get very durable high-tech shell materials that are super-light, but they’ll cost you more money.
What About Your Sleeping Pad? (Hint: it matters)
A sleeping bag can only do so much. If you have a rubbishy sleeping pad - or worse still, insist on sleeping on ground or on some old foam cushion you dug out of your garage - don’t expect the sleeping bag to perform at it’s best.
When backpacking in winter, do make sure that you take a decent sleeping pad, with a high R value - it will make all the difference to your comfort and how well your sleeping bag is able to keep you warm.
Getting the Most Out of Your Sleeping Bag
Top Tips for a good night's sleep on the mountain:
Whether you are camping on Kilimanjaro or Mt Kenya, or sleeping in huts and lodges on your way to Everest Base Camp, here are our top tips for getting the most out of your winter sleeping bag: