At those temps, I usually layer with a silk base layer, fairly light wool long john layer topped off by a relatively light jacket (often my Cabelas rain gear jacket). A commando sweater wears easily under the jacket if a bit more warmth is needed but adds little bulk. Layers can be added or taken away if the temp changes. Above all, good wool socks are crucial, as is a warm hat. Remember the old adage, "If your feet are cold, put on your hat."
Also, I have been using Asbell's as well as La Clair's wool over a light under layer both with good results.
It sounds like your temps are similar to my local conditions, and I have found that it is often best to carry in some of these items, putting them on when I get to the stand. If I sweat on the way in, I will be uncomfortable no matter how I dress.