I'm up in Maine and have had a great experience with Descente's Wombat glove in cold weather. I've found that it works best for me from about 20* to 40* (at an endurance-type riding intensity). A bonus is that it's got a pocket on the back of the glove that stores an attached finger "hoodie" that acts as a windshield for your fingers at lower temperatures. When not in use, it tucks easily and neatly into the pocket. I've found sizing true-to-size, durability is very good, they aren't very bulky and they have an elastic wrist that seals nicey around all of my riding jacket cuffs. You can find them at a variety of online shops at significant discounts:

http://www.backcountry.com/descente-wombat-glove

Another review of the gloves:

http://www.commuterdude.com/...e-wombat-gloves.html

Also, in truely cold conditions those small, disposable chemically activated handwarmers work wonders. http://www.amazon.com/...02M802/dp/B003DQELD0 Just activate them and slip them in between the glove and the back of your hand.

If that doesn't work, time to go to the gym!