Some good suggestion already given here. This is really my first year riding in cold weather, but am a year-round runner here in Southern Ontario. Some of the same strategies would apply to riding--layering, starting out feeling colder than is comfortable, no cotton, etc. But the one thing that I found even riding in 5*C is that my fingers and toes are frozen after an hour. Mittens or thick gloves and winter riding shoes/shoe covers are a must. Running in 5*C is quite pleasant. Riding in 5*C feels much colder.