I ride my bike in to school, and am just now (well after I'd need to leave to make the bus) realizing that below freezing (atm -13 celsius) might be a bit chilly. I have a windbreaker and good gloves, what else do I need?
Some sort of ear covering for sure. I have several depending on how cold it is. Chilly = earband, colder = skullcap under helmet, colder still = balaclava + earband or skullcap, really freakin cold = quilted hardhat liner under oversized helmet.