What does the 2-3 seasons rating mean on a sleeping bag? Does it literally mean you can only use it for a couple of seasons or does it mean something entirely different?
2 seasons refers to spring and summer, Evers. 3 adds autumn. I think that's the general idea. A 4 season bag would (supposedly) be suitable for winter.
Better going off the temperature ratings. Erm. Or not.
Better going off the temperature ratings. Erm. Or not.
The temperature rating should give you a rough idea of the temperature at which the sleeping bag will keep you comfortable. Some bags also include an 'extreme' rating which is the temperature at which they suggest the sleeping bag will at least keep you from freezing even if you're going to be pretty uncomfortable.
But it all depends whether you're a 'hot' or a 'cold' sleeper. Do you, for example, sleep starkers with just a sheet over you and the bedroom window open through the winter? Or use a 13.5 tog duvet all through the summer? Or somewhere sensible in between?
You should ideally try to get a sleeping bag appropriate for how 'hot' or 'cold' you sleep. Unfortunately if you don't sleep 'normal', it can take a bit of experimenting to find out what's right for you. It took me a £120 sleeping bag to discover that I sleep iceberg cold. Fortunately I was able to sell it on...
just to confuse you, we at EB also do a "3+" category, which is, I guess, 3 and a half seasons, just not the depths of winter. Nope, not much clue either.
Of course it's all relative to how you sleep, but I think in general ratings trend towards conservative. Fear of litigation, as much as anything else. A liner of some sort can chuck in a few extra degrees, at least.
I think it's also true, from what people say, that below a certain temperature the whole ratings thing just doesn't really work, which is why people sleeping at minus 25 might not take a bag rated all that way.
Below zero, as in the temperature falls below freezing. Note, however, that even if the ambients outside are down below freezing it may well be above that in a tent or a bothy. You might only get a couple of degrees better, but that's often enough to make a big difference.
> Below zero, as in the temperature falls below freezing.
Yes, but to be fair (if somewhat pedantic), that could be quite a range... 'below zero' covers the range 0C to -273C, so it's not a very useful rating...
'Down to 0C' might be more useful, and why bags are now usually specified with with 'comfort' and 'extreme' temperature range ratings.
I'd ignore the season ratings, as it is very vague and often not that accurate. It varies a lot between manufacturers. Stick to using the temperature range, as this has to be measured to a precise standard.
Stick to using the temperature range, as this has to be measured to a precise standard.
Even that doesn't work in the 'real' world, as such.
The test is on a dummy in a lab. at a constant temp. that stays 'still'.
Doesn't account for wind, rain, tent, sleeping mat used, temp. rising/ falling during, condensation, tossing and turning, etc. etc.
Nor wheather you sleep 'hot' or 'cold'. IE. take me, I sleep 'very hot', I know that I can sleep comfortably, in shorts, at -5c, in a bag that is rated +5c. If I add baselayers I can use to @ -10c. By comfortably I mean I won't be cold, sometimes to warm.
But then I'm not 'normal'. Everyone sleeps different. As said it can be a 'minefield' in finding what bag suits you.
On the assumption that you might be buying a bag, borrow something or even try a couple of cheap 2nd hand bags. Fake a camp, ie on your lawn and go from there. At least you will get an indcation of how you sleep. Make life hard as well. Go to bed hungry and cold, you can always sort that in minutes at home. If in doubt overdo the insulation a touch or carry another layer.
i'm planning my first winter trip to the highlanders i have an 3 season sleeping bag an bivi bag but i unsure if i should use an micro fleece, fleece or silk liner
A winter trip to the Highlands implies you want a four season bag, winter being the fourth season. So if you only have a three season bag I'd add in as much extra oomph as you can. A silk liner is mainly about keeping the bag clean and isn't any more warmth than pyjamas. Having said that, you can wear extra layers in bed as pyjamas, and if you've got fleece top and bottoms that's useful outside the bag too, where a fleece liner isn't.
