I'm preparing for a 2014 thru-hike and am going to be bringing a sleeping bag rated near 0 degrees (with a sleeping bag liner) since I already have one. I am also planning to be using a Blackbird hammock, single layer with a Thermarest prolite sleeping pad.

I know my sleeping bag will be compressed, thereby rendering the down insulation underneath me next to useless. However, I'll also have the sleeping pad under me, so that may help some.

My question is what temperature rating should I be looking for in an underquilt, or would I need one at all?