what temperature bag do i need?

[ausvegguykk]

so i have had a bit of discussion on this before, but i am still considering things..

i am riding from sydney to adelaide beginning of january, the warmest time of the year, and i have been looking at 0c sleeping bags, but im wondering if i actually need that for this time of year

hay (about half way there) has a record low temperature for january of 5.5c and an average low of i think 17 degrees c

any suggestions? maybe i can get away with a cheaper 10 or 15c bag, with a bit of clothing

i am taking a bivvy bag and a thermarest mattress most likely

cheers

[undercling-mike]

You're probably not going to need much at that time of year. If you're planning to head through alpine areas then 0C could be a reasonable rating to aim at but if not then I think a 10C rating is what I'd look at for this particular trip.

[johnk1]

A rating of 10c will be plenty .

[paul_gee]

Do you want to invest in a bag that's going to cover you for this and similar trips only, or would you prefer to have a bag that can be used in a wide scope of temperatures?

If the former, then a warmer bag should suffice - something in the 5-10°c band.

If the latter, then a 0°c bag is a good place to look. Heck, some folks use -5°c bags as their allrounders; especially useful if you want to hike in places like NZ and Tasmania too.

My recommendation - always go a bag warmer than you think you'll need. Why? Because you can always just use it as a quilt if it's too warm.

When I cycled the Great Victorian Rail Trail in February the night time temperatures were well into the 20s on all bar one night. I didn't use my bag as a quilt even, it was too hot, so I laid on top of it. But the first night was in the single digits and having a 0°c bag was welcomed.

So, what I am saying is, if you plan to do other trips in the future think forward to what you're likely to need for them. You can buy a bag for every occasion if you want, but that soon becomes very expensive. Or you could buy one, quality bag that will suit most occasions.

[slparker]

remember that a bivvy bag will add a considerable amount of warmth to your sleeping system, depending on wind/rain/overhead cover.

if it gets down to single digits i would be very surprised if a 10 degree bag/quilt in a bivvy bag does not keep you warm and you could always carry a lightweight down jacket or vest to boost warmth - you are probably going to carry warm clothes anyway - why not wear them to bed if it gets cold?

i don't agree that you should pack a warmer bag than you'll need (except if walking in the mountains). Pack a bag for the expected conditions and boost your warmth with stuff you already have, especially on a bike when weight and room are paramount.

You can really overheat in a bivvy bag if you are stuck in it in warm wet conditions that are too cool to go without some insulation but too hot for the sleeping bag that you are carrying. Makes for a terrible night's sleep.

[gayet]

Also consider how warm or cold a sleeper you are, and allow for this in your decision.

[ausvegguykk]

Usually i am in another country for almost the entire winter, and i would probably prefer not to camp out in miserable winter conditions anyway, it would mainly be for AUS spring/summer/late summer conditions (about september- march/may)

[undercling-mike]

For 3 season use on Aus mainland not in alpine areas a true (for you) 4-5C rating would be a good option. It wouldn't cover every conceivable scenario but sounds like it would work for the majority of what you're likely to do without increasing in bulk/weight/cost too much.

[andrewa]

A different approach.....I now use quilts, which keep most of the down on top, and the sleeping mat underneath provides insulation there. This has become possible in the last 10 yrs ish, due to improved insulation from sleeping mats. I also sleep in whatever clothing I need to keep warm. I also make my own gear, which gives me some freedom in design.

I made a summer quilt with 200g of 900 loft down ( total weight 450g) . It was just OK for me down to about 8c in NZ. I added another 100g of down, and it is now a much more useable summer quilt, but I also use a lightweight down/synthetic insulated jacket as well, if needed (eg Montbell extra light).

In winter in the snow, I use a home made quilt with 500g of 800 loft down (total weight ~750g) but I sleep in a down jacket (RAB neutrino) and down pants, which I also use outside the quilt. This works all through winter in Victoria in the snow.

So, I suppose it comes down to how you use your clothing and sleeping systems together, rather than try to give you a "temperature" value on a bag, I'm trying to convert this to amount of down...and a quilt might use 2/3 of the amount of down than a sleeping bag for the same warmth, as most of the down is above you.

Don't believe temperature ratings on bags. I think the amount of down fill, and the quality of down is the issue. Design makes a bit of a difference, but less than the other factors. Have a look at quilts - they are lighter and more comfortable.

Undercling Mike, on these forums makes some beautifully designed quilts, balancing weight and warmth.

A

[drakkar]

A sleeping bag is part of a 'system' not a stand along component.

In my cheap vaude bivvy. I can get away with nothing more than a s2s reactor and some light thermals Down to 8c or so. Only around 15c in rain or wind...

Is it a bag purchased just for this trip? Or will it see future use?
Or will it become a summer bag and you will invest in a winter bag as well?

With a good sleeping Matt in a bivvy assuming you aren't in alpine regions. 8-10c comfort will be ample. Add some thermals and better wind/rain protection and you might sneak up to 4/5 degrees beyond that in a pinch. You might also have a very uncomfortable night or two

[Moondog55]

More like
"If the worst and coldest conditions ever recorded for this area at the time I am there happen and are a tiny bit worse will I have enough of everything to not get hypothermia.
Conversely and perversely if you prepare for the worst then it will probably T-shirt weather every nite, but if using a bivvy to keep the wind off and an UL tarp for rain and radiation shelter then a LW synthetic bag comfortable at ~18C combined with thermals, socks, the ubiquitous beanie and a warm parka should let you survive a nite close to freezing