Re: Staying warm while backpacking in cold weather, and bivy's
There are some water proofing sprays like Scotchguard and Nikwax that you could look into.
I have a down bag but, I let the wife use it. It might be a bit warmer than the synthetic bag, I’m not sure. I use the synthetic bag nowadays because it suits me fine and it was cheap to buy (I paid $75 for it used) and easier to wash.
For base camp I use a nice big LL Bean synthetic with a flannel liner. It’s a lot nicer against the bare skin.
"A true conservationist is a man who knows that the world is not given by his fathers, but borrowed from his children." John James Audubon