For having a comfortable nights sleep, I'd single out these factors:
- Proper ground isolation (your clothes and sleeping bag is compressed under you, so you need to buy a good sleeping mat or make yourself a good substitute).
- Having a sleeping bag rated to your conditions
- Having a comfortable position
- Staying dry
- Not too windy
- Not being eaten by bugs
In not too bad weather, a tarp plus sleeping bag plus ground mat is a splendid way to spend a night outdoors. Much more roomy than any tent can provide. Much less clammy than a bivy bag and most tents.
Depending on temperature and local fauna, you might want to think about how to avoid mosquitos and bugs. Some bug net to cover your face might be plenty unless you're claustrophobic or want to unzip your sleeping bag to adjust for the not-so-cold nights.
If you need a full size bug net then the weight and bulk of that plus a tarp is pretty close to some of the minimalistic ultralight tents out there - but those are expensive. I'd be very sceptical about ultra-light and ultra-small cheap tents. And ultralight and ultrasmall means clammy (unless they're very successful at designing ventilation, which equals expensive) and crammy. Me, I'd go for a tarp for anything but the most extreme conditions.
My confidence in tarps stops at very strong winds (exactly how strong depends on your ability to find the best location in your terrain) and the combination of wind and snow.
Oh, and you don't want anything smaller than a 9-by-12 size tarp.
Edited by MostlyHarmless (11/09/10 09:34 AM)