I am taking a trip in late February. We will be camping two nights in the George Washington National Forest in WV, near the WV/VA line. I expect the lows to be around 15-20 at max, and hopefully around 5-10 higher then that.

I have a Kookabay R5 pad on the way, and I plan to take my Z-Lite underneath, which is R2. I have a Montbell #5, 40 degree bag. I also have good layers including a down jacket I can wear.

My question is...Do you all think I will be ok with this setup? Or alternatively should I carry along a 2nd 30 degree synthetic bag I have, and double bag up? Carrying the 2nd bag adds 2lbs to my base weight, which pushes me from about 9lbs to 11lbs base. I am just wondering if the combined R value of 7 along with good layers in the Montbell bag will be enough or not.

Thoughts?

Thanks!

If I were you, I would take just the synthetic bag in this case (that is if your synthetic bag is true to it's rating)

The #5 would probably be ok to 35 and maybe 30 with added insulation from clothing. I'd take both bags to be safe, assuming they are appropriately sized for nesting and won't cause compression of your down.

I tested the other night inside with the down bag inside the synthetic. The synthetic bag is larger and there was not a ton of room between the bags, but did not feel cramped. I was still able to stretch out the Montbell a bit and did not feel overly constrained.

I might test this in the backyard one night before I head out.