What do you wear in your sleeping bag when it's cold?

[Colter]

I'm trying to get an idea of what most people do for maximum warmth in cold weather.

I know opinions vary. Some swear sleeping naked is warmest, some that piling on the clothing is warmest, some that just a base layer is best.

What works best for you?

[rp1790]

Well, I've always thought just piling on the thermals and then down jacket was the thing to do (and then the rain gear!) but have recently read something that said that actually prevented the bag doing it's job. So, am interested in general opinion on this as well.

The article I read basically said you should just wear a light set of thermals and anything above that was counterproductive. Yeah, I know, doesn't necessarily "seem" to make sense.

[kayak karl]

In winter i strip down to briefs, socks and wool hat. nothing worst them wearing damp clothes to bed in cold weather. I sleep in a hammock and this has worked down to 0 degrees so far.

[mudhead]

Define cold. I saw what Fairbanks had last night.

I do hat longjohns thick wool socks. Dry, clean, as can be. In reasonable chilly weather.

[Franco]

Sleeping warmer when naked can be true IF:
you otherwise wear DIRTY/WET clothing , even just dirty socks. (note that otherwise is not wise)
and or IF the SB becomes too tight and you compress the loft too much by doing so (this to a lesser extent)
BTW, regardless you sleep warmer when clean.

Very easy way to prove this.
At home turn the heating off in a room (could be the bathroom...)
Put your mat down and get inside your hopefully underrated bag.
Wait for half an hour or so. Put some thermal clothing on . Get back. Do you feel warmer or colder ?
Next night repeat in reverse order . Once you have taken your clothes off wait at least half an hour before you decide.

Of course if your bedroom is already "cool" try with and without thermal clothing under your blankets.

I have switched from a 20F bag plus thermals to a 32F with a light down jacket and pants as well as socks and hat if required.
The tot amount of down is about the same , the weight (in my pack...) is less because the pants and jacket I have with me anyway.
Again it is important not to sweat in those clothing so that they are dry when you get into the SB.
(I carry eVent rain gear for wet snow and have as few layers as possible when walking. IE I don't wear down when walking..)
In really cold areas (that is -30 plus) you need to wear clothing so that you don't lose too much heat during toilet breaks.
Franco

[Papa D]

You know Tipi Walter hasn't posted in a while and I can assure you that he has slept out in weather colder than about 96% of the people here - I've been out at -18 or so Fahrenheit with wind temps at who knows what, so, I'd say that I'm qualified. I assume we're talking REAL cold here, right?

Speaking of Tipi - I think he is on a 20 day Joyce Kilmer, Snowbird Mountains trip - testing out his cold weather gear and safety equipment

25 degrees - fed, peed, long johns, good down bag like Western Mountaineering, Mont Bell, Marmot, whatever
15 degrees - pretty much the same rig plus wear your stocking cap - add a nalgene hot water bottle (don't cross- thread - have extra fuel) - Western Mountaineering 5 degree - overstuffed bag
5 degrees - both nalgene bottles full of hot water - wear stocking cap, socks, and gloves - add wearing down jacket if you want - I transition to the Feathered Friends Bag
When it's really cold (4 degrees to negative 20) I'm in my overstuffed -30 degree Feathered Friends Ptarmigan bag with the Mont Bell Vapor Barrier.
On top of this, I have to have extra fuel or absolutely reliable wood burning stove or fire because you must boil your water. Your water is stored in your bag with you in the form of Nalgene (or steel in socks) Hot Water Bottles - this serves a duel purpose of keeping you toasty warm and making sure that the precious water doesn't freeze. I also wear, my down jacket, down pants, and down booties at crazy temps like this. - It is also difficult to backpack more than about 8 miles a day in temps like this - the snow is usually deep.

[Colter]

Define cold. I saw what Fairbanks had last night.

This is my thermometer this morning.

53 below.jpg

But I think cold is relative. If it's 20 degrees with a 25 degree bag, that's cold!

[Papa D]

This is my thermometer this morning.

53 below.jpg

But I think cold is relative. If it's 20 degrees with a 25 degree bag, that's cold!

dude, you're in Alaska - cool - well, -53 tops anything I've slept outside in - I've winter camped at Ruth Glacier but it was about -5. I've also done lots of days at -10 to -18 but I don't know what to say about -53 - that's beyond my pay grade. Really?

[stranger]

I don't sleep naked but I do believe that the more clothing you wear in a sleeping bag, the colder you will be. Sleeping bags have a single function - to trap air. Then the person inside the bag heats up the air trapped = you are warm. Wearing clothing restricts the ability to heat up the interior air = contradiction. How does it work in practice? Who the hell knows...all I know is that the more I wear, the colder and more uncomfortable I get - plus I don't like wearing much when I sleep anyhow (do you really want to sleep in a parka?). I wear lightweight long underwear tops and bottoms at night regardless of temperature, allows me to move freely inside the bag (not stick to it cause my skin is all grimy), keeps the bag clean (clothing gets dirty not the bag), I don't do it for insulation purposes. I also recommend wearing socks for the same reason. I know some people who swear by wearing their camp clothing in their bag and going with a lighter bag, it doesn't work for me, I've tried. The coldest night I had in 2008 was while wearing a down sweater inside a 25 deg Western Mountaineering bag, woke up about 15 times that night cold..... I had a night a week later that was colder...I just wore a light shirt, and slept through the night.

If I'm concerned about the temperature or the ability of my bag to function, I shake all the down to the top, I eat something just before going to bed, I do some light exercise before getting in the bag and I put on a down hat. Wearing a good, down hat will keep you warmer than anything else in my experience.

[wornoutboots]

I agree the more clothes you sleep in the colder you will be. In my down bag, naked is the warmest after hiking all day because my body continues to put off heat & it interacts with the down. It all depends though on the moment, a few weeks ago at Cold Spring Shelter, I was there with Sabi & Ripple, 2 flip floppers & it was snowing hard when I go there shortly after dark. The snow blew in on us all night long & it made my bag damp & I had to put all my clothes on in the middle of the night to stay warm & sleep. It was 10 degrees that night but I still did OK with my 15 degree bag

[Tinker]

It's absolutely false that a base layer alone is warmest. If you have enough room in your bag, adding insulation can't help but make it warmer. If your bag is tight, any clothing you wear into it will get compressed and add little to your warmth.
Tip: if your bag fits tight, but you want to add some warmth, lay your down jacket over your bag when you go to sleep. Often it will slide off, however. I read somewhere that you could sew matching Velcro patches onto your jacket and bag to hold the jacket in place, but stitching into a down filled garment is risky unless you stitch through the perimeter seams.

Now, if you wear too much into your bag so that you sweat, you may find yourself cold when your body's metabolism slows down as you fall into a deep sleep, and the cold gets to your sweaty clothing.

I sleep in my base layer and down jacket and pants in my hammock in the winter. Sometimes I add a second, lighter bag. Whenever I need to get up, I don't have to rush around trying to pee as quickly as possible before I freeze to death.

I had to edit this in: When I was a newbie hiker I bought a bag which was much warmer than I needed it to be (and heavier). Over the years I found that

the concept of LAYERING can be used in a sleep system.

That is why I wear down clothing into my bag. If I did a thruhike NOBO, I would start off with a 40 degree and a 50 degree bag (nested) to be warm down to around 5 degrees with a down jacket and pants (which I could wear around camp). If there was an unexpectedly warm night (or nights, as on my '06 Georgia section hike in March), I could use either bag, with or without down clothing inside, to give me a comfort range of +5 to +50 (and then some) - far more of a range than one could possibly get from a single bag.

My 50 degree bag weighs exactly one pound and is semi-rectangular with a full zip and fits me like a glove. I have to wear my jacket over it and under my 40 degree bag,

which weighs 1-1/2 lbs. , so I'd be carrying essentially a 2-1/2 lb. bag which, with my clothing, gives me that +5 - +50 (and warmer) range. The clothing I would carry anyway, so I don't count it as part of the sleep system, but just fyi, the pants weigh 8oz. and the jacket with hood weighs 17oz.

[Tinker]

Sleeping warmer when naked can be true IF:
you otherwise wear DIRTY/WET clothing , even just dirty socks. (note that otherwise is not wise)
and or IF the SB becomes too tight and you compress the loft too much by doing so (this to a lesser extent)
BTW, regardless you sleep warmer when clean.

Very easy way to prove this.
At home turn the heating off in a room (could be the bathroom...)
Put your mat down and get inside your hopefully underrated bag.
Wait for half an hour or so. Put some thermal clothing on . Get back. Do you feel warmer or colder ?
Next night repeat in reverse order . Once you have taken your clothes off wait at least half an hour before you decide.

Of course if your bedroom is already "cool" try with and without thermal clothing under your blankets.

I have switched from a 20F bag plus thermals to a 32F with a light down jacket and pants as well as socks and hat if required.
The tot amount of down is about the same , the weight (in my pack...) is less because the pants and jacket I have with me anyway.
Again it is important not to sweat in those clothing so that they are dry when you get into the SB.
(I carry eVent rain gear for wet snow and have as few layers as possible when walking. IE I don't wear down when walking..)
In really cold areas (that is -30 plus) you need to wear clothing so that you don't lose too much heat during toilet breaks.
Franco

I just read your post, Franco. It looks as though you have thought this out (and/or have some long-term experience). I could not agree more with your assessment.

[Colter]

Most of us have heard a saying to the affect "remove layers before you get too warm, add layers before you get too cold." As a rule of thumb, I think the same is true with a sleeping bag and clothing.

When it's very cool or moderately cold, I'm most comfortable with just a base layer, usually with clean, dry, sleeping socks, long underwear tops and bottoms, and a balaclava. If I put on my down jacket in my bag I'd likely sweat and end up colder. But if I can tell my sleeping bag is going to be marginal for the night, I'll start out with my base layers AND my down jacket on. Personally, I'll be warmer that way, for sure. One thing I know wouldn't work for me if I was chilled would be to take off a major insulating layer in an effort to warm up.

I don't understand the logic that "if you wear clothing in your bag you can't heat up your bag and you'll get cold." Why can't your body warm up the air in your bag? Because your clothing is retaining the heat next to your body. That's the point! That's a primary reason layers work, there are dead air spaces between the layers. Perhaps there are people who get really cold feet at night though, for whom their body heat needs to circulate in the bag at night to warm up their feet. Needless to say, people vary.

Layering has to be done right. An extra layer of wool socks will generally keep your feet warmer, but they can make your feet colder if they cause your feet to sweat excessively or if they constrict your circulation. An extra layer when hiking will keep you warmer unless you end up sweating which will make you colder in the long run.

[TRAUMAhead]

I have a Katabatic Gear Chisos (16.7oz) with 2oz overfill, making it from a 40* to about a 30* quilt, 9.1oz total down. I've only had the bag down to low 20s once, and I was a little less than comfortable wearing my Rab Microlight Alpine jacket w/ hood, synthetic tee, midweight longjohns, nylon hiking pants, and two pair of SmartWool socks. If I had down booties and threw on my balaclava, I think I would've been comfortable, and I'm on the cold sleeper side. I was also using the tuck method so I got drafts every now and then.

Before the quilt, I had a 15* and 20* bag, and only slept in my shirt and boxers. I always have my down jacket with me, so I figure I'd put it to use in my sleep system. I usually relax outside my tent after getting to camp, so I figure I'll add the down pants to help keep warm, which would also supplement the sleep system. And I know getting a warmer bag is lighter than the bag + puffy clothes, but wearing puffy clothes in camp before sleeping and in the morning is nice.

[keithclove]

I always change to a clean base layer before turning in...

[Rocketman]

It's absolutely false that a base layer alone is warmest. If you have enough room in your bag, adding insulation can't help but make it warmer. If your bag is tight, any clothing you wear into it will get compressed and add little to your warmth.

Now, if you wear too much into your bag so that you sweat, you may find yourself cold when your body's metabolism slows down as you fall into a deep sleep, and the cold gets to your sweaty clothing.

.

So, it seems to be true that adding insulation can't help but make it warmer but if you wear too much [insulation] into your bag so that you sweat, you may find yourself cold.........

You might want to change some of the detailed words.

[Kerosene]

I made several mistakes using my then-new WM UltraLite 20-degree bag my second night out in Georgia in April 2004 when the temperature was to drop below freezing. I attempted to wear all of my camp clothes to bed and this may have compromised the loft of the bag. In addition, I'll bet that my old Thermarest Prolite 3s wasn't up to the task of insulating me from the cold ground. Now, I don't usually sleep very well the first few nights out, but it wasn't a very comfortable night at all.

[Smooth & Wasabi]

I have to agree with others who say more clothes = more warmth. In my experience I believe without a doubt that if you have some room in your bag and your clothing is dry it is warmer to wear your clothing. This is part of the reason I went with a MB UL SS #3. I have plenty of room to wear puffy layers without compressing the loft. The last trip I used this bag (30f bag)on it was about 34F but with snow/sleet/rain so I got pretty chili from hiking and I went to bed with my puffy on. About an hour later I was too warm so I took off the puffy and was nice and toasty but not overheated for the rest of the night. Now this would not work if I tried to fit my very large frame with a puffy layer into a WM summerlite or other such snug bag or if I went to bed with my wet clothes on.

[wornoutboots]

A lot of it also depends on the person, I sleep very hot so for me the less clothing the better.

[TeamLoblolly]

I've never had a problem becoming cold after bundling up and sliding into my sleeping bag. In very cold situations, I wouldn't want to be in my boxers.