Metro are running the following:
Christmas Eve: Saturday service until about 6.00pm, then hourly service (30 minute between Pelaw and South Gosforth).
Christmas Day: No Metro service.
Boxing Day: Weekday service without the additional peak services. 
27th-30th: Normal weekday service (minus peaks on 27th)
New Years Eve: Saturday service until about 10.00pm, then a 30 minute service (15 minute between Pelaw and South Gosforth) until end of service.
New Years Day: No Metro service.