I'd like to reinforce the warning about cotton jeans. My then teenage daughter (who insisted on being fashionable to the point that I gave in) wore jeans on her second backpacking trip. On the trail in, we missed the rain, but the waist-high brush and grass along the trail was soggy and quickly soaked us from the waist down. The air temperature was about 60*F, with a bit of a breeze. I noticed that she was unusually quiet, but it wasn't until the first rest stop that I realized she was shivering and becoming somewhat incoherent. I set some kind of speed record getting the tent up, stripping off her soggy jeans, bundling her into two sleeping bags (hers and mine), heating hot water bottles and brewing many cups of hot cocoa. She was already hypothermic enough that she couldn't have helped herself!

Needless to say, the next trip she wore a pair of Air Force surplus tropical weight polyester and wool pants, and never again insisted in being fashionable on the trail!