Bushwalk Australia

I received my overland track map kit from TASMAP in the mail last night, and was reading the information on the back off the 1:100000 map, and under "What to take:", it says it is essential to take a "sleeping bag rated to -5C. (-10C is better).".

Does is really get that cold? I currently use a 0 degree bag here in NSW, even in winter (I've been comfortable down to -5 in it without thermals or a liner). Are they just covering their backsides, or is it really "essential"?

Yes it does. It occasionally gets down to -5°C in winter at my house in Tasmania, which is about 10m above sea level.

On Tasmania's central plateau, -5°C is likely to happen a few times a year in summer, and frequently in Winter.

My current sleeping bag is rated to -7°C and I've been cold in it once (it was winter, at altitude similar to the OT). My old sleeping bag was rated to around -12°C and I was never cold in that, even sleeping outside on the verandah of an OT hut with snow on the verandah around me.

PS. Check out the BOM page for Cradle Valley climate showing "all data" at: http://www.bom.gov.au/climate/averages/ ... _All.shtml

It shows that they can get down to -8.5°C at Walheim in August (which is lower in altitude to most of the OT).
Some days it doesn't get above zero at all (in winter).

It can get down to -1, -1.3, -1.9°C in summer at Waldheim, but again keep in mind that it can be even colder on some parts of the OT which are at higher altitude.

Also note that the MET measures temperature at a standard height of 1.5M above the ground and the actual temperature at ground level can be a lower again.

Thanks for the link Nik.

Going by that, the coldest it's ever gotten in February is -1.9°C, and that was 40 years ago. If I calculate correctly that the highest campsite is Waterfall Valley at around ~1050m and subtract (roughly) 2 degrees for altitude that is ~-4°C. If I have been comfortable at -5 in my 0 degree bag, I guess I'm asking does a Tasmanian -4 (with a new record) feel colder than a NSW -5?

I don't really want to spend several hundred dollars on something when I already have one that will do the job. Or would I be better just buying a thermal liner just in case?

It's hard to give definitive advice, because everyone's different in their sleeping patterns, temperatures, and what's comfortable.

But if your sleeping bag keeps you warm at -5°C, then I reckon it should be OK for the Overland Track in February. It would certainly not be warm enough for me, but then I don't have very good internal temperature control, like to sleep with the tent door open (screen door closed), and don't like wearing clothes to bed.

If you're certain it was -5°C then you should be OK for February, I reckon. But be prepared to have to wear extra clothes to bed, if necessary.

That was a quick reply!!!

I think I will stick with my existing bag, but will get a liner and take thermals (I was taking thermals anyway). If a really good sleeping bag deal comes up I may be tempted into one, but I don't think I'll write one on my "To Buy" list.

And if I do happen to get cold I'll get a new one for the following summer