on keeping warm in cold and damp weather....I'm in Washington State. Its ALWAYS cold and wet here, but we manage to stay comfy even in downpours and snow with the following:
1. wool!!!!!! it stays warm even when wet, wicks water away, is water resistant and oh-so period. wear it on your feet as stockings, even two pairs at a time. Wear it as the garments themselves. I wear a woolen gown and a woolen coat.
I've been to events in the pouring rain. the water wicks off the shoulders and drains to the cuffs of my coat. The cuffs and bottom will be wringing wet but the shoulders will be basically only damp, since the water has been running down the coat itself, and I'm dry underneath.
poly-wool blends dont do this, only 100% real wool, preferrably the fully fulled stuff (ie you threw it in the washer and dryer before you made it up into a garment)
2. cover your head. Preferrably in linen with wool on top of that. Silk is good as under wool also. Cotton does NOTHING to keep you warm and polyesters dont breathe so they're no help at all either (plus being modern. ugh). I wear a linen head cloth plus a woolen hood that covers my head and my shoulders. I have a wool coif that I sleep in when the nights reach into the 30s.
3. Mittens of wool are wonderfu. I have a pair of sheepskin mittens just like the period ones the sheepherders wear.
4. pattens (those are wooden overshoes that go over your medieval leather shoes) are a godsend. They keep you out of the wet a bit so that you dont lose heat through the bottoms of your feet. I dont know about you but if my feet are cold its hard for the rest of me to keep warm.
hope this helps! its actually neat to be portraying people while wearing medieval clothing (ie wool and linen) in medieval weather. You'll be warm and fairly comfy while the folks running around in plastic garbage bags over cotton tunics with watch you with envy 
--Anne-Marie