If you plan to get out on the trail during the colder months, or are heading to altitude, a good winter sleeping bag is essential.
Hiking in frosty conditions or at altitude is hard, and after a strenuous day, getting a good night’s sleep is difficult 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.
Do you need a Winter Sleeping Bag?
Maybe not. These are 'extreme' rated sleeping bags, and for most cases, a 3-season sleeping bag should suffice. A winter sleeping bag is for camping at altitude above 10,000ft, for snowy, icy conditions.
It'll be overkill to buy an extreme-rated bag if you are only using it in shoulder-seasons and at low elevations.
And if you're heading out in the warm, summer months, consider a summer sleeping bag.
0F (-15C) Down Sleeping Bags
These are the warmest sleeping bags for their weight, but 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 a consideration for winter backpackers on unsupported treks.
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.
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 normally be.
Note: if you plan to camp at Crater Camp, Kilimanjaro – I'd 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, 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 a major consideration, 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 unwell, these can be left lacking.
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.
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. This is because they are based on what the “average” person finds comfortable or otherwise.
They are an attempt to standardize the conversion from an insulation value to a temperature range. But they don't take into account that there are many variables contributing 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 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 they also take no account of 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.
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.
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 so you stay warmer through the night.
This shape makes the bag less bulky for fitting into your backpack without compromising on warmth.
Mummy-style sleeping bags have a hood to secure around your head, and a neck collar to prevent 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) design 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 size.
Most high-end models 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 I've yet to find 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. But, 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.
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.
Synthetic insulated bags are bulkier 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 synthetic is 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! On camping trips I just make 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 want gear that packs down into the smallest size and weighs as little as possible.
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 bag can also have an effect on it’s compressibility, the mummy-shape with their tapered cut tend to compress smaller than the rectangular ones.
Tip: if your bag doesn’t come with a compression sack, then get yourself a waterproof one. It will keep the bag dry in your backpack and make it as small as possible.
Weather Resistance and Durability
Whilst it won’t be waterproof, it’s important that the bag 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 shells 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, make sure that you take a decent sleeping pad, with a high R value - it will make all the difference to your comfort.
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:
See more top tips for a good night's sleep in our guide How to Stay Warm in a Tent.
*Product Images credits: © Amazon.com