Originally Posted by Miguel
You'd be surprised how well a good shaking works. If it's rained during the night but is not raining when I break camp, usually wipe my tarp down with a shamwow. If it's still raining about all you can do is give it good shaking. Either way I place it in it's own stuff sack and carry it on the outside of my pack. It really won't make much difference if it's damp when you put it up the next night. It will either dry out when hung or get wetter again if it's still raining. Either way you should remain dry under it. It's not much fun when it rains for several days.
I was surprised when I weighed my tarp first when it was wet, then after shaking, and then again after wiping it down with an absorbent cloth. Step three is worth doing too. I use two pieces of cloth, one in each hand, and let the tarp hang vertically from the ridgeline. That way I can dry both sides at once and apply pressure with the tarp between my hands. (Before I release the side tieouts to let the tarp hang loose I can dry condensation on the underside - there's enough tension on the tarp to do just that side.) I think the drying step helps even with a light rain falling (work fast!). YMMV.