Sleeping bag temperature ratings.

10:44 p.m. on August 11, 2007 (EDT)

I live in Southern California, the temperatures here are pretty laughable when compared to other places. I am planning on getting a sleeping bag and am deciding what temp rating to get.

Realistically in the next 5 years or so I expect to see temperatures of around 0-15 degrees at the lowest. Within the next year probably not even below 40. In fact the vast majority of my backpacking will be done during either blazing temperatures or what most people would refer to as warm weather.

I feel getting say a 15 degree bag would be a mistake for me, as I've heard many tales about unzipped, feet out, only half on the person, but sweating to death from people with 0-15 degree bags.

I plan on purchasing a 40 degree bag and a liner, this way I figure I can COMFORTABLY take anything down to 25 degrees. I plan on buying another bag between 0 and 15 degrees later on when I get into the cold weather stuff (traveling, really). I was wondering if this sounded like a good idea or a bad one.

I also tend to sleep extremely hot.

10:47 p.m. on August 11, 2007 (EDT)

I was also thinking if I just got a bag liner I could probably be fine till about 50 degrees, but then I think it's pretty unsafe if temps dropped too far because of a storm or misc weather factors. I could buy the cold bag and carry both just planning on using the liner, but man, that's just unnecessary space and weight.

I figure a liner down to 50 degrees, a bag at 15, pretty big gap to be uncomfortable in.

11:01 p.m. on August 11, 2007 (EDT)
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I have two sleeping bags. One is a Mountain Hardwear 3rd Dimension (Polargard) that I bought around 2000 or so. I believe it's rated at 0 degrees, but I can't use it in weather anywhere near that cold. I can get by if I wear thermal underwear and heavy socks, down into the 20's, but any colder than that and that bag doesn't cut it.

Last year I bought a Marmot Couloir (800 fill down). That one is also rated at zero. I used that at the Grand Canyon in December when the temp got down to around 15, and did just fine. I felt like I could have still done fine even if the weather had been colder. The bag was really comfy, and in fact the hard part was getting OUT of it into the cold morning air :).

So now I use the Mountain Hardwear bag in the summer in the Sierra, and I'll use the Marmot again when the temp starts dipping down into the 20's.

I've also read that down bags offer a wider range of comfort than polyfill bags. That might be a factor in your decision.

Anyway, this approach of having a summer and a winter bag seems to be working well for me - as long as I know what weather to expect before heading out :).

I also have a true "summer" bag (rated at 30 or so), which I could still use if I camp in any warmer climates (like SoCal in the summer :). (I'm in the SF Bay Area)

11:56 p.m. on August 11, 2007 (EDT)
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Plenty of great 40 degree bags out there. sounds like your on the right track to me! enjoy

12:02 a.m. on August 12, 2007 (EDT)
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Woops, you will be cold at 25 degress in a 40 bag. But it sounds like you will rarely see 25. Seems kind of silly to get a 15 degree bag if you will mostly use it in 70 degree weather. I have two bags a 15 and a 40 I've taken the 15 degree down to 7 degrees and was chilly but alright and the 40 with a silk liner down to freezing and I was very very cold! Maby you can just rent a 15 bag one those rare cold outings from rei untill you can afford to buy one

12:13 a.m. on August 12, 2007 (EDT)

Oh forgot to mention, the current plan is for a Marmot Arete for now, and a Marmot Pinnacle later on.

11:00 p.m. on August 18, 2007 (EDT)
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One way to increase the rating of your bag is to use an overbag. I have one I got from MEC, the Canadian company (sort of their REI)that I use with my 3 season bag. Not the most efficient way to sleep in winter-bulky and not as warm as a full on winter bag - but in my case, it adds about 10F to my bag's rating, which makes my 23F bag about a 15F bag. I then pile my down parka on top and I'm good for a few more degrees cooler than that.

I think that is a good alternative to buying several bags since I don't do all that much winter camping, yet like to get out and do a bit of snow camping in the Sierra (Yosemite).

10:45 p.m. on September 6, 2007 (EDT)
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In my opinion these temperature ratings merely tell you where you'll experience the onset of mild hypothermia. You won't die in your sleep, but you won't sleep comfortably either. Heck, you probably won't sleep at all when it gets that cold because your bag isn't toasty-warm any more.

Like you, I "sleep hot," so I want a bag with a bottom-unzip capability. I open the bottom of my bag and stick my feet out like radiators until the temperatures get down to around freezing. Then I zip it shut and pull the mummy bag's hood down around my head. My bag of choice is a 20-degree bag. I live in southeastern Virginia where our winters are pretty mild. I'm a Scoutmaster and I camp year-round with my Boy Scout troop. I use this three-season (aka 20-degree) bag most of the time.

I use my 20-degree bag any time the low temps drop below 60-degrees. Above that I use a quilted poncho liner that I bought at an Army surplus store thirty years ago.

Even though I have a 20-degree bag I ALWAYS put my poncho liner inside it once the overnight lows get to about 40-degrees. If I don't need to use it, then it becomes stuffing for my stuff-sack "pillow."

BTW. I have a -15-degree bag that I use only if we go camping in the mountains during the winter. It doesn't have a bottom-unzip capability, and I can't stand sleepng in it unless the temperatures are hovering between +15 and zero. Otherwise it's way too hot.

Here are some more helps for maximizing overnight comfort:

Once the temps drop below freezing start wearing a toque (aka 'toboggon' hat) to bed. Not the one that you wore all day. Keep a second one in your bag.

Don't sleep in what you were wearing during the day. It will be moist and those damp togs will soon make you miserably cold. At the least, change into a dry pair of underwear before turning in.

Extend your bag's range by wearing a pair of silk long johns to bed.

Learn your bag's limits by sleeping in it with as little clothing on as possible. Bring a thermometer and look at it when the cold wakes you. This is your bag's true comfort limit. It may be 15-degrees above the bag's rating. Fix it by adding a poncho liner or wearing a pair of silk long johns.

1:35 a.m. on September 7, 2007 (EDT)
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As WB implies, bag ratings can be deceiving. However, bags sold in the EU, such as MacPac bags have to pass a standardized test, so you can compare bags from different manufacturers. For example, if you look at the test results on MacPac's website, you will see the range of temps of the their bags' ratings and what they mean. Here is an example-

With American bags, I have no idea how they get rated, so can't say about them.

9:40 p.m. on September 7, 2007 (EDT)
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all very good info.

I wound up with a Marmot Arete, living in southern california I figure it's my best chose for what I'll face the most. I also took the advice of getting a warm liner, I got a Marmot Trails on sale.

I'm a bit pissed about the Arete though, so far I love the bag, but REI lists it as a "full length zipper" but in fact it stops before the feet. no idea why the mixup, or maybe just bad phrasing.

I also plan on snagging some silk long johns, I hear you don't get much better for a hot as hell base-layer

1:42 a.m. on September 8, 2007 (EDT)
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I have used a down 20F in the eastern Sierra for 3 seasons. It has at times been in the 20's in August at altitude. I think the coldest night I have spent was in BLM desert, however.

That bag is now worn out and I will probably get another 20F for the same reason.

Many nights I have laid on top of the bag, but usually inside by early morning. I have wrapped my pad with fuzzy stuff and sleep on it with bag over when it is too warm.

Have toyed with the idea of making a quilt bag

and making up the weight difference in sleepless nights or wearing everything I brought. Or, buy one already made up

REI has a 20% off sale this weekend.

I think the bag ratings represent the temperature you can live through, not necessarily a comfy rating.

3:09 a.m. on September 8, 2007 (EDT)
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Silk gets a lot of recommendations, but I have midweight Capilene from Patagonia and have worn mine for years. I have bottoms and a long sleeve turtleneck top. Mine are over 20 years old, get used a few times a year and are still in very good condition.

May 21, 2018
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