From the description it could be protein buildup
But it could very well be that you just need to use a heavier conditoner. It's not that cold here in South Carolina either but on the dry days I swear I nearly have to use a dT just to get my hair to look normal. And my hairs not dry or damaged either.
2c/3a?
Low porosity, medium texture.
http://public.fotki.com/Medusahair/

If it smells good put it in your hair, if it tastes good spit it out!