The cleaning and conditioning will help but cold weather keeps the leather from bouncing back. I would suggest a good cleaning and multiple light coats of conditioner. Heating the leather up with a hair dryer while the conditioner is soaking in will help it bounce back into shape. I use a heat gun in cold weather but you have to be very careful not to overheat the leather. A hair dryer would probably work best for you since there is usually one in every household.