Unless you live in a country that has a warm climate all-year around, it becomes very difficult to enjoy biking during December -- that is, until you try the A'ME Heated Grips.
Sure gloves are an option, but they can be bulky and it may not provide the best grip; this is where the A'ME Heated Grips come in. These have internal heaters that are powered by an 11.1 volt lithium-ion battery pack that's attached to the handlebar stem. Worried about it getting wet? No worries, there are watertight connects that allows this contraption to be used in the snow and in the rain. There are six temperature settings in total and the gripping surface is a patented Vulcathane rubber which guarantees that hands won't slip off.
It may not help with body heat, but the A'ME Heated Grips are a start to making winter cycling more comfortable.