Sleep Warm Anywhere

Let me emphasize something: The picture of me sleeping outside in the snow is not a good idea. I did not sleep well. But I did survive, and since then I've learned some tricks that would've kept me plenty toasty. Many of these seem like common sense when you read them, but you'd be surprised how few people think of them. I didn't, without a lot of trial and error. Here's what I learned so that you don't have to make the mistakes I did.

Keep in mind that most of these techniques assume dry weather. If it's raining or snowing, the steps are the same, but you'll have to do them inside your tent or vestibule. It is also assumed that you have a sleeping bag rated for around the same temperatures you're likely to be experiencing, but the techniques demonstrated here can give you some wiggle-room with that. Remember: being prepared is always step one.

As always, anyone see something I'm doing wrong, could be doing better, or should be doing that I'm not, let me know!

Also, with the exception of the two intro pics, they're all staged on a closed course by professionals, but rest assured that these techniques do work. Hopefully, they'll help you get a better night's sleep, and in doing so help you better enjoy the great outdoors.

Step 1: Put on Your Fly.

This seems like a no-brainer, especially with a mesh-canopy tent like mine, but it's very, very important in frigid conditions. Not only does your fly block wind, keep in heat and keep off rain or snow, many tents are actually designed so that the fly helps prevent condensation, and a dry sleeper is a warm sleeper.
The fly also provides a vestibule, which is an extremely useful thing to have, especially in windy or rainy situations.

On the downside, it does block your view of the stars, but I can forgo marveling at the majesty of the cosmos if it means not freezing to death.

Step 2: Use a Pad

Many of the big tough hikers or ultralight junkies out there spurn the use of the pad--as did I, until I got a bag that requires one. This is fine, normally; granite's as good as a box spring from my point of view.
But when you're in extremely cold conditions, and especially when sleeping in the snow, it's a must. This Big Agnes pad is my favorite, though it takes about a half-life of plutonium to inflate, but virtually any pad will do. Closed-cell foam is obviously better for hiking in areas where punctures are a risk, and many prefer the convenience of self-inflating thermarests. As long as you have one, it doesn't really matter.

Step 3: Dry Off

A dry sleeper is a warm sleeper.
Well, unless his boxers are full of dry ice, obviously, but it's a good rule of thumb. Before going to bed, make sure you're dry. If you just got done hiking, you could be covered in sweat, or if you washed your face before bed, you might be wet as well, though admittedly cleaner. Do what you can to get dry. If your clothes are damp, switch into a dry set.

Step 4: Dress Warm

Since I posted this guide, there has been a lot of back-and-forth in the comments section about whether or not this is actually a good idea.
However, I must maintain my position, due in no small part to the excellent links provided by the thermally impressive gmoon, particularly this one.
I recommend a synthetic fleece vest or wool sweater and a knit cap.
The vest is light, dries quickly and is quite warm.
The sweater is even warmer and in my experience slightly more compact than fleece for the same amount of warming.
Both remain fairly insulative even when damp, unlike cotton sweatshirts which are literally worse than nothing in wet situations. Though I prefer the wool sweater overall, synthetic fleece is nice in that it absorbs almost no moisture, whereas wool takes on the approximate density of depleted uranium when it comes in contact with water and is very reluctant to dry. One other noted difference between the two is that wool is all but fireproof, whereas any synthetic cloth is prone to burn quite easily and melts while burning as well, adhering to skin like overpriced napalm. While this is usually a minimal hazard, small sparks from a campfire are notorious for burning little holes in synthetic clothing.
The hat is amazingly warm, and while I usually use wool knit, synthetic is also excellent.

I should also add that the inestimable zwild1 reminded me of the importance of the bag liner. This is a cloth (I use synthetic fleece) liner which goes inside your sleeping bag. It can improve the rating significantly. Good suggestion!

Step 5: Get Warm Fluids Into You

This is probably the most pleasant step. Sitting out in the cold after a long day of communing with nature, there's very little that's nicer than a warm drink. I personally prefer tea, but hot coco and hot drink mixes such as apple cider or gatorade are also favorites. The purpose of this step is twofold: it warms you up and it hydrates you. There's virtually not part of camping that is worse off for better hydration, and sleeping is no exception. Don't overdo it, though; a cup or two is good but past that you're probably in for a nighttime hike to the tree. You should also eat something, obviously, but if you haven't figured that out you probably shouldn't be camping.

Step 6: Get Warm Fluids Out of You

You're going to be spending the next several hours getting you, your clothes, your sleeping bag and your tent comfortably warm, and all that's gonna go to waste if you find yourself having to wriggle out of your bag for a tree-run. Answer the call of nature before you go to bed, and you'll be a lot happier.

Step 7: Make a Hot Water Bottle

This is an excellent trick. Just before bed, fill a lexan bottle with hot water and wrap it in some clothes. This is also a twofold step: It'll warm you up initially, and you can drink it if you get thirsty in the night. Just make sure that lid's on there tight.
Many people have suggested the use of rocks instead of a water bottle, but believe it or not, water stores more heat at a given temperature than stone. The measurement of how much heat a given volume of something stores at a given temperature is called volumetric heat capacity, and water's is about twice as high as granite's. To put it simply, if you heat a liter of water and the same amount of stone to 212 degrees Fahrenheit, the water will release about twice as much heat as it cools to the ambient temperature of your bag.

Step 8: Sleep Tight.

Crawl into your cozy bag and drift to sleep in the great outdoors. Keep an eye out for signs of trouble, though--when you first get in, you'll be warm, but when your body becomes sedentary it's likely to cool down a bit before your sleeping bag warms up. If you keep getting colder, you may need to add more clothes, but don't constrict yourself. Place your hands in your armpits to keep them warm. If you're shivering and stop but are still cold, congratulations! You've got hypothermia! Get moving. Make yourself more tea and a fresh hot water bottle. Use your head. Sleeping in the cold doesn't have to be dangerous, but it's always risky. Know how to deal with these situations.

Of course, if you've followed these instructions and aren't at a polar research station, that's not likely to happen. Most likely you'll awake in the morning, refreshed, ready for a new day, and contemplating whether or not you'll survive the shock of transition from the warmth of your bag to the frigid hellscape of the tent.

I hope this has been useful. Good luck!

Comments

[haclil]

Hold on there, not all of us can hold it in all night! Our bladders
just don’t have the endurance of past years—well, quite a few
years past. We’re your, shall we say, senior backpackers. And as
such, we loath the cold blast upon exiting a shelter in the middle of
the night.

My sleeping bag has
a handy built-in pocket just big enough for a few sandwich bags or
small ziplocs. You can see where this is going. Find a little space
next to your bag or even on it, maybe going down on your
knees....


If you don’t fancy
closing the sandwich bags with a tie the ziplocs are for you (at the
cost of a bit more bulk). Where you put the warm bags is your choice;
inside the bag not recommended.

[Daveamd44]

I'm surprised you didn't touch on heat loss. With most of your body's heat loss through your head, covering your head (leave just your nose out for fresh air!), in the same area as your body (for example, a blanket or liner within the sleeping bag, or better yet, if the sleeping bag is large enough to pull over your head) recycle's the lost heat from your head, back to your body! I almost always do this, because I love heat! (Kind of like peppers, the hotter, the better! Like Carolina reapers...) Anyway, good tips so far!

[scoutysteve]

Hi, I'm a scout leader and we often have our first camp of the year in sub zero conditions, sometimes in the snow. We ensure the scouts take two sleeping bags and double them up, one inside the other. This trick works well, with no smurfs! to date. Even more important for the leaders, sleeping in tents alone.

[JeffM198]

Hey, super valuable article. I also found this one, which gives a few more ideas about how to keep your tent warm: http://campingandcamping.com/10-tips-on-how-to-ke...

Cheers

[cstar4004]

On a week-long hike, i learned the hard way not to sleep in my clothes. We were instructed to sleep naked, or in underwear, and to use the clothes to line the sleeping bag, rather than to wear. i did not listen, and the first night out, i woke up at 4am, freezing and sweating at the same time. Your clothes will make you over heat, whoch in turn makes you sweaty and wet, which than freezes. Clothing also slows your body heat from filling the air inside the sleeping bag. You will get warmer, faster when naked.

Another tip, youre body loses energy to heat up fluids that you drink. And naturally, you lose body heat when you urinate. You can recycle some of this lost heat by peeing into a bottle, and cuddling with it in your sleeping bag, just like the hot water bottle idea, listed above. And just like the author says, make sure the cap is on TIGHT. I would not recomend drinking the urine, however, if there is no water to drink, drinking your own urine can keep you alive for a few days longer than drinking nothing at all. This is what the experts have learned, climbing the highest peeks. This is more of a dire emergency tip, and most likely not needed for your everyday, backyard family-camping.

[felipemehr]

Before I go to the sleeping bag I do a little run, short enough so I don´t get sweaty, but long enough to get some heat from muscular activity and then staight into the bag. Also remembre that the head is one of the parts, maybe de one which most looses heat...

[107]

another thing to remember is that if you are using an air mattress, you don't want to blow it up with your mouth. In cool weather it is ok, but if it's winter, all the moisture you used to blow up your mattress will freeze, and we (hopefully) all know what you sleep on is one of the most important things.

[Yonatan24]

Is there that much moisture...?

[CookieRojas]

This is impossibly well-written. A+++

[Kandiklown]

Ok i love the idea ... To add onto it what about for when your hicking your bag remains warm ...how u ask with solar powered heating pads... Just an idea.. Let me know if that ould or could not work

[WaksupiC]

I've camped at minus 40 for a week at a time. Some need to go experience it, to see that their presumptions don't always work out as expected.

[sweerek]

'How to Sleep Warm Outside Cheap'

1. Make a $15 R10 sleeping pad from EPS foam (bought from Lowes or HD). See how-to at http://www.slideshare.net/sweerek/di...ordian-27mar15 . Then put a comfortable, summer, non-air, pad atop this warm but rigid base. Contrary to JAK, you'll lose ~ same heat down as up.

2. Use your existing summer bags as the base layer. If you've two such bags, use them both. (Walmart's $20 bags layered & fluffed up are a good value.)

3. Depending on how much room you have and travel means (car? sled?), bring polyester or down comforters and place over your bags (like a quilt). Fluffy pillows too. These can be bought cheaply at GoodWill / thrift stores. Since these are cotton, consider how you'll keep them dry.

4. If below zero *F and/or you'll be out for days, use a Vapor Barrier Liner (VBL) as your first blanket layer to mitigate evaporative heat loss. This can be any plastic sheet, rain poncho, emergency foil blanket, etc. VBLs not only reduce heat loss but also keep your gear lighter. (Frozen water vapor is heavy.) The color (even reflective silver) doesn't matter one bit because radiative heat lost is (delta T)^4 and the delta-T is near zero.

5. Wear a thin poly (wicking) balaclava and thick loose fleece balaclava at bare minimum. I sometimes wear a stocking cap in between.

6. Wear your wicking - fleece - puffy layers of winter clothes to bed. (Except if you've a VBL, then puffy layer goes outside of VBL.) Your shell / parka can go atop or underneath. Insure yer not cramped or constricted in the least; all layers and stuff should feel loose.

7. Bring your boot liners, hot water-bottle**, chemical heat packs (as a late night back-up), and mitten liners to bed. ** Only use a highly-trusted, never-will-leak bottle. Fill with near boiling water, put inside insulated bottle holder, and use to keep feet warm.

8. Use a snowshelter, tent, tree-cover and/or anything else to block the wind, add some warmth, and radiative heat loss to the sky.

9. Go to bed warm -- eat well, jog a lap around camp.

10. If cold at night, do sit-ups.

[gshaffer1]

oh, yea, have a bloody good sense of humour, laughing keeps you warmer.

[gshaffer1]

okay, two points from a guy that has slept cold, not be choice, in bad gear and has since been with SAR and trained for 8 years to sleep in the cold and wet comfortably. Most of it is well covered in this instructable, awesome Job!! and what he missed is covered in the comments well, but my two cents are: Firstly and as a top priority, make sure you are not losing heat by conduction. protect yourself from the ground with the most insulating products around...tree litter, wood, packs...animal, friend. This is the most important item to consider is what you are sitting/lying on. Secondly, do not over heat. Sleeping too warm will create a huge sweat that will kill you in extreme situations. Wearing an adequate warmth is a skill that only practice can help with as it is so personal. for example, I need cool feet to start, followed by warm feet for continued comfort...not easy to accomodate! thankfully I have a well trained dog that can put my socks on while I sleep.

Now, Do not assume, even with all the reading in the world, that you can go and sleep cold no problem. You must practice. practice practice. Finally, as my last and worst case scenario, Ill share with you this life long helper, If you are really cold, and there is nothing more you can do to warm up, place your nose outside the bag and your mouth inside the bag, breathe deep through your nose and exhale warm the air through your mouth, trapping the warm air in your bag. There are so many reasons this shouldn't work and could be bad, and I have no arguement with that, but it works for me. I do not feel the obvious extra condensation one would assume would build up, I do not feel as if my insides are cooling down to compensate, but I do feel warmer almost imeadiatly and I breathe deeply, which helps with sleep. To be honest, I can never really remember breathing more than a few times prior to sleep. Interestingly, the body has a completely different set of heating parameters while we sleep, so thats another blog.

[whitepinoy]

Too many years in Boy Scouts with military leaders led me to give this explanation. When sleeping outdoors the key to staying warm isn’t so much as the pad that you use. The key is layering. The earth sets off heat all year long. No matter what the outside temperate is the earth is going to be warmer or cooler depending on the season. So what we want to do is use that temperature to regulate the heat in our bed. The best lesson that i have every received for camping was from and Master Sergeant Army Ranger who told me that when you sleep it is key to place 2 layers below you for every 1 layer on top. With this technique I have camped in -20 degrees weather and stayed toasty. And yes I only wore a hat. If you wear clothing it is more likely that you will sweet at night and not be comfortable. The other thing is not so much the bag or whether or not you wear clothing to sleep in it is whether or not you have the right size tent. If your tent is too big you will never be able to warm the air in your tent and you will be cold. But, also if you are cramming 3 men into a 2 man tent you are going to get extremely hot (I have done this thinking I would freeze on night). There is more to say but I think you get the idea.

[-chase-]

I must disagree with something you stated - though the earth gives off heat - it absorbs it as well, as in the case of body heat. - this is well known through out the camping/outdoor world. You layer or pad the earth side first and formost - to prevent body heat absobtion. Then cover.

I do like your layering idea rule of thumb - interesting. Your Sargent knew of the absorbtion of body heat by the ground. hence he told you about layering.  ie; padding on the ground side.

- Air pads do not do as well as a foam pad for insulating you from the ground from what i found.

[Bjorno]

Air is the best insulator from heat... period. IF you inflate it properly, an air pad is far superior.

[SIRJAMES09]

I will never ever use an inflatable matteress/pad of any kind.

I have had too many experiences where the matteress/pad sprung a leak.

Now what I use is closed cell foam for insulation between me & the ground & open cell on top of that for comfort(softness).

Closed cell foam thickness = 4 inches
open cell foam thickness = 6 inches

I forgot to mention that between the 2 foam pads, I have a piece of plastic sheeting 10mm thick.

I never ever freeze. not even in a blizzard.

[Mother Natures Son]

That's 10 inches of foam...and 10mm of plastic isn't a sheet, it's a slab! how do you carry all that?

[A.A2]

i like math, too.