Clothing
There is a range of clothing available depending on the weather and terrain. You can get quite uncomfortable on the bike seat, so mountain biking shorts or pants are made with padding to help keep you from getting quite so sore. For the cooler weather there are: arm warmers, balaclavas, jackets, jerseys and tights. Jerseys and jackets should keep you warm, dry and cool and durable.
Good socks are also important as they will prevent blisters and keep your feet warm.
There is also mountain biking armour and padding to help protect your elbows, arms, knees and legs in case of an accident, they also help keep you warm in the cool.