Synthetic Overquilt Temperature ratings

Given the variables – humidity, metabolism, etc. – it's going to be tough to be sure. But as a starting point I'm making an overquilt (2.5 oz climashield) and going on the assumption (based on copious but less than scientific research) that I'm going to get about 15 extra degrees out of it when added to my summer bag. So, if that is correct, then it ought to keep anything from freezing in my bag down to about 17 degrees, right? Using the same assumption you'd need an overquilt that adds 32 degrees of warmth to be sure you were keeping the freezing point out of the inner bag. Or so it seems to me.

That's what I was thinking also Paul, Tim Marshall mentioned to me before that each 2oz of Climashield adds about 10f.

So my synthetic quilt will only protect my bag from internal moisture above 22F (below ir will still protect it from external moisture.

You don't need an overquilt above 22 F. Water just evaporates. For one thing, there's a boundary layer of air that has about 10 F temperature drop so inside your sleeping bag it's above freezing. I sleep at temperatures that cold and haven't measured increased down bag weight.

I think that a synthetic over quilt would be for 10 F or 0 F or colder. And many days. I have no experience though…

Cheers Jerry,

Your right, I got the overquilt for 10f and co