I have not been that way in January but last May there was snow on the Somosierra north of Madrid and there are lots of warnings on the road regarding Snow. I would look into the need for chains
Dave
not sure about road condition information, but you will get some idea from the spanish met. site www.aemet.es/es/eltiempo/prediccion/espana You will need to put in cities en route but it is a fairly easy site to understand.