I usually wear arm coolers which allow my arms to stay reasonably warm- then I wear a Showers Passing rain coat with a mesh insert under the shoulder flap, pit zips and will roll up small enough to fit in a pocket on the jersey. I carry a pair of disposable gloves for tire flats or to keep my hands dry. Under my helmet I wear a buff which although it doesn't keep my head dry, at least soaks the water away and wicks much like wool. Of course, most of the rain I ride in (Texas and the south don't you know) is warm enough that my concern is more about trying to stay cool enough than warm enough. That being said, I have ridden with the above combo in some fairly low temps and while I haven't been toasty warm, I at least have been warm enough to function. I love my showers pass rain cioat and my arm coolers.