Planning travel beijing with parents on dec12, how is the weather on dec? what equip i need prepare?

It is the middle winter time during Dec. It is dry and chilly, with an average temperature of -6~4C. You need to prepare thermal underwear, a woolen sweater and a down coat at this time to well protect you from the chillness. Warm gloves, scarf, hat and mask are also indispensable.