Mountain biking in cold weather has always been a challenge. The problem is that you'll start out cold then warm up and break a sweat, making yourself wet. Then, when you travel downhill, the combination of wet skin and windchill will be quite chilling.
Below, you'll find a list of the cold weather clothing that will make winter riding less of a bone chilling experience.
Booties
In cold temperatures, your feet are the most vulnerable part of your anatomy. Pressure from pedaling will tend to cut off the circulation to your toes, which can put you at a risk of frostbite. In cold conditions, neoprene booties are a must have. They will zip over your shoes and even have a pattern in the sole where you can cut out a piece for cleats.
Gloves
There are several manufacturers that make "lobster gloves", a hybrid glove that separates your index finger and thumb from the rest of your hand. These gloves are warmer than regular gloves, and the distinct index finger will allow you to operate your shifting and brake levers.
In case your hands get cold, you should carry a pair of lightweight glove liners will you as well. If you have to stop to take care of a problem, the liners will protect your hands from the cold.
Glasses
Glasses that wraparound and provide maximum protection from the wind are best to wear in the winter. You can protect yourself from debris, as well as the cold.
Socks
You should wear heavy socks although not to heavy. A sock that is overly heavy will make your shoes tight, cut off circulation, even make your feet cold. You should try lightweight socks, as they will keep your feet warm without bulk. If you need an extra layer, try silk ski socks as they are very warm and also extra lightweight.
Underwear
Polypropylene is the best material here, as it is lightweight and best for colder temperatures.
Wind protection
Moving air is the biggest cause for losing body heat. By having good wind protection you'll be able to vent perspiration while also protecting yourself from windchill. You should choose pants and a jacket based on durability, breathing, and price as these types of clothing can get very experience.
Helmet and liners
Your head is very important, as you lose 50% of your body heat through your head. A helmet is designed to keep you cool in the summer, not warm in the winter. A fleece liner inside your helmet will keep your head and ears warm during winter mountain biking.