So what is the general consensus on what temperature rating to shoot for when considering a three season bag? I'm a relatively warm sleeper and I'm looking (ideally) for a bag that will be comfortable from March/April through October in the Western US and Canada (Rockies, Cascades, Sierra Nevadas etc.) I have a thin synthetic bag for super warm temps (summer camping not in the mountains) but would like to be able to get just one other bag for everything else but cold winter camping. Is a 20 degree bag going to be too warm in summer temps? How far would I be able to push a 30 degree bag? What are people's opinons around here?

As a side note, the bags I'm currently considering are the WM Ultralite/Summerlite, FF Swallow/Hummingbird/Merlin/Osprey and the Montbell UL Spiral Down #1/#3. Any thoughts on these bags?

For the conditions you describe, I'd want a bag that is warm down to an honest 28-30F. So this would probably be a 30F bag if it is indeed good to 30F, but if you are cold sleeper or the bag is optimistically rated then a 20F bag might be a better choice. Also, if you want a greater margin of error for abnormal nights then a 20F bag might be a good call.

FWIW, I've used a 30F bag down to about 20F by laying my jacket on top and other gear. So your decision does depend on what other gear you have too.

BTW, The MEC Merlin -3 C (27F) is probably a really nice 3 season choice. It's priced great at $220-$240 Cdn (about $200 USD) and it has 800fp down. At just 690g (24oz) it's pretty darn light. It's not as light at my GoLite Ultra 20 quilt (which is probably similarly warm) but if you want a traditional bag then you aren't going to do much better than this and especially not for this price.
http://www.mec.ca/Products/product_detail.jsp?FOLDER%3C%3Efolder_id=2534374302701483&PRODUCT%3C%3Eprd_id=845524442624886

Edited by dandydan on 08/13/2009 23:52:31 MDT.

I would go with a 20F bag if it is not too much of a weight penalty and if it gets to warm you can always quilt it out

I have used several light bags in warm conditions and my current and probably last choice, at 63, is my WM Alpenlite Super, a 20* rated bag. I have had an MEC bag, among many others and do not think much of them, or, most other MEC gear, although I like and use some of it.

I joined MEC not long after it was founded and I have used a fair bit of their "house brand" gear, quite a lot of which was mediocre in design-quality compared with WM, ID and Hilleberg, for example. For light bags, I prefer the current WM "Extremelite" series to any others.

I'm a warm sleeper (maybe very warm???)- a 30 ° bag does me well for three seasons in the Rockies (Montana). Most of the higher end 30 ° bags seem to be rated pretty true. As mentioned above, w/ a little addition of some clothing you can easily extend that range.

If you do go the 20° route- I'd insure it's full zip, my 30° bag spends much of the time zipped open @ both ends during the summer months- a 20° bag would really spend a lot of time unzipped.

I lived alone in the Alberta Rockies due west of Edmonton, where the OP seems based for periods of several months, from April to Sept.Based on temps. in June and July below freezing and the snowstorms, I would defintely choose the 20*F bag and I just "quilt" it in warmer temps.

I had a WM "Overbag" rated to 30*F plus a Bibler Solo Dome while there and while a very warm sleeper and used to cold and wet weather, I would have prefered a warmer bag. This is why I "retired" my FF bag and bought the WM Alpinlite, among the nicest bags I have ever had and it's quality is like that of ID and Valandre bags...it don't get no better.

I would go for an honest 30 degree bag and layer in. Use insulated top and bottom that you might use around camp anyway as part of your sleep system.

I have the summerlite and the ultalite. Last year I used the summerlite on top of a clearview bag. It was August in the sierra. I wore all my insulation and I was just on the hairy edge of uncomfortable. I felt like if I had some insulation out of the pad I would be OK. I bought the ultralite for this year and am struggling with which one to bring.

My message here is definitely consider the insulation value of the pad in your decision. If I had a neo-air I think I would try out the summerlite again this year.

I am throwing my vote for a 30 degree bag for three season use. The bag will take you down to freezing but still be light enough for some 50+ degree nights. A 20 degree bag I would consider almost a four season in most of the westcoast where any winter temps I've come across weren't lower than 10. A bag like the megalite is great because it has enough room inside to layer a big puffy jacket if you are going someplace where colder temps are expected.

Dewey: "I joined MEC not long after it was founded and I have used a fair bit of their "house brand" gear, quite a lot of which was mediocre in design-quality compared with WM, ID and Hilleberg, for example. For light bags, I prefer the current WM "Extremelite" series to any others."

It's true that not all housebrand MEC gear is great, but it is normally a really good value. A comparable bag to the Merlin -10 C would cost about $500 which is about 60% more (or $200) than the Merlin. When you consider that MECs warranty is amazing (if you don't like it, they'll take it back for a store credit even after several years) it's worth giving it a shot. Also, the simplistic design mentality that makes a lot of MECs gear affordable also keeps it light.

I know, the point to me is that I have had quite a lot of MEC gear fail over the years and this happened in places where warrantees mean nothing as I was too far into the bush to do anything about returns.

So, yeah, for basic recreational backpacking and hiking, MEC stuff can be OK, but, I go places and for long periods, that require better gear than most of it.

Their winter down bag is made in China and looks like a "knock off" of a Valandre Shocking Blue...and, having thoroughly checked one out as well as owning a VSB, there is NO comparison!

I don't worry about price, I want the best in function and will have it and then find the coin to pay for it.

Edited by Kutenay on 08/14/2009 22:08:09 MDT.

I've got a WM Summerlite, and I love it. It's roomy enough that I can wear a down sweater inside if I need to extend the range a bit. I find that it does pretty well if it's shielded from wind.

Still, in April or November in the Cascades, I think the WM Summerlite might not be enough.

In addition to the WM Summerlite, I have a MH Phantom 15 which will take me through even some winter outings if the weather isn't too bad or the elevation too high.

It depends on if you want to stretch the envelope or not. If you do, then get a 30 degree bag along with a nice puffy jacket (which you may own anyway) and be prepared to sleep in that most of the time. You have to know your own sleeping and hiking style. For example, do your legs or feet get cold at night? If your feet get cold, you will need to bring something extra (as your feet are probably warm in your shoes). If your legs get cold, then you have to ask yourself if you bring leg insulation for the daytime (long underwear or insulated pants). If so, then re-use makes sense. If not, then bringing extra clothes just for the sleeping probably doesn't makes sense (might as well get a warmer bag).

If you aren't prepared for that much fussing (which may take some trial and error), then get a 20 degree bag. For the area you mentioned, it is probably the most common one used. As said earlier, the weight penalty is rather minor (once you've made a sleeping bag, it doesn't take much insulation to add extra warmth).

As far as particular bags are concerned, FF and WM make excellent, top of the line bags, so picking between models is probably more important than brand. For models, it depends to some degree on how much room you want. Montbell makes excellent bags as well. I believe their down is not quite as good but still excellent (if FF and WM is a 10, Montbell is a 9) but their spiral and stretch bags are quite innovative. These bags allow you to stretch, while still retaining a very efficient, warm bag. I own a FF and Montbell stretch bag and I'm happy with them both.

I have a WM Megalite bag. I got that model because its larger girth makes it more versatile. If I wanted to stay light in colder weather than the 30 F. the bag was designed for I would go the "multiple use" route to keep weight way down. This means I'd wear my ThermoLite insulated pants & jacket to bed (& a balaclava). This would keep me warm to at least 0 F. That Megalite is warm enough by itself to at least 25 F. I know B/C it was that cold on the PCT this week at the South Fork of the Kern River camp site. (I wore my REI Sahara pants and LS synthetic shirt to bed for more coziness the second night.)

The insulated jacket and pants would also be worn in the morning for making breakfast and breaking camp. At about 1.5 lbs each they would add weight but necessary, "mutiple use" weight.

So look at it this way, a 30 F. bag will be fine for most nights. Colder than that and you can add long johns or, as I said, even insulated pants and jacket, clothes that you WILL need anyway for the morning chores. With a decent sized 30 F bag you have versatility. I use my Megalite zipped open and the foot hooked over the end of my mattress for a very comfortable quilt on warmer nights.

Eric

Edited by Danepacker on 08/16/2009 18:10:05 MDT.

It depends on your altitude. August conditions are quite different in the Cascades than in the Rockies.

Last Saturday night in Wyoming's Wind River Range, the temperature was 22* at 9300 feet (Elkhart Park trailhead ). During the day it snowed a foot in Titcomb Basin (11,000+ feet). Yesterday, conditions were similar at Elkhart Park (snowing!) and I'll bet that conditions were similar to the previous Saturday at Titcomb Basin, too. Last year, at this time, temperatures were in the low 20's in the southern Winds ("backside" of the Cirque of the Towers, at Shadow and Pyramid Lakes) during the second week of August. There was frost at night in the northern Colorado Rockies the first week of August.

I'd go for a 30-degree bag for summer in the Cascades and a 20-degree bag in the Rockies. By the time you get to late September, both ranges will have nightime temps in the low 20's or the mid-teens.

A lot depends on whether you're a warm or cold sleeper and how much you want to depend on supplemental clothing to keep you warmer than the limits of your sleeping bag. This is something that only you can determine.

I have been cold at night, and its' not fun. You have some good options above, and in general, a 20 usually has draft collars, maybe more beefy hood and draft tube than a 30. I vote full zip 20, easier to be hot than cold. But layering for sure comes into play, as does how many times will you be out pushing the temperature envelope? Are you spending a lot of time in camp, when you will need good layering anyway? That might lead more to a 30 choice.

I always want to be hot at night.

Thanks a lot everyone for the replies - they have been very helpful. Right now I'm leaning towards the 20 degree bag (likely Feathered Friends Hummingbird or Swallow). After looking at historical weather data for some of the regions I would be in, I could easily see myself looking at overnight lows well below freezing (average lows between 0C and -5C with record lows between -10C and -15C). I don't think the 30 degree bag would cut it in these temperatures. Out of interest, what is the warmest temperature anyone has used a 20 degree bag in (quilted-style - the full zipper is pretty helpful in this aspect)?

I used my WM Alpenlite Super in August, 2008, near my hometown of Nelson, B.C. and it was HOT the week I was there. I use it as a quilt then and it had to be 75*F one particular night, so, I slept ON it, inside my ID bivy and IT was unzipped.

I would point out that your uses and whether you go solo or not enter into this. I DETEST sleeping in my clothing, ESPECIALLY insulated outwear and it can become pretty damp from doing this. I have done it and do carry a Wildthings "Elephant's Foot" plus my ID Dolomitti parka as my winter emerg. bivy setup.

However, if solo, you NEED to take injuries and awaiting rescue into account and THIS is where the 20* bag really is superior. If, you sustain a fracture, you may well be "shocky" and feel COLD...the 20* bag will offset this at close to 30* FAR better than the slightly lighter bag.

I will not carry a bag in the Rockies at ANY time of year that is not capable of keeping me warm at 20*F, even nude and injured. I know I seem "old fashioned" to some here...but, I will put my wilderness experience, SAR experience and general "time in grade" against anyone here, where western Canadian situations are concerned.

Anyhoo, that is what I think.

I actually agree with Dewey on this one...having been one of those injured folks waiting out a rescue. And trust me on this one-if you have a broken leg, you're gonna want a fully unzippable bag at the least. Trying to manipulate a broken leg into a zipperless bivy bag is really not fun...

Injury? Well then should we not carry a ton of Trad gear just in case?

The whole idea of an UL sleep system is to combine gear carried for additional warmth thereby reducing redundancy and overall pack weight. Lets not forget that.