OK, I just came back from a run-walk, which was mostly a run. Considering it was my second run in about 10 weeks, I did OK. Three miles, and I ran most of it, including up the hill. It was 38 when I left, cloudy and windy. When I got back, it was 43 and the clouds had broken up just a little. I unzipped my outer layer (a Wild Roses light fleece jacket) after about a mile and that was fine until I starting running up the hill at the end, when I took it off and tied it around my waist. I had on my fleece headband, Smart Wool liners, a Terry wicking hoodie, and a sleeveless Craft base layer. Oh and wool socks.
I wasn't running very fast and in fact, did not wear my Garmin on purpose. But it felt good.
I do sweat a lot, but when it's cold, the sweat just seems to chill me.