Excellent Winter Jersey
I live in Massachusetts so the winters are pretty intense. I searched the site for a thermal jersey and only Louis Garneau has long sleeve jerseys that are labeled as "thermal". Castelli's Warmer fabric is Castellis warmest fabric evidently and IS thermal. Under 40 degrees you'll need a windproof shell but this jersey performs very well at keeping you insulated. Don't jump up too many sizes because the thermal fabric needs to be in close contact with your skin. I'm 6'3 230lbs. and wear an XL.