Faro is the administrative capital of the Algarve, region of Portugal Apart from Ilha de Faro, 8km from the town, it is not a tourist destination itself.
Be aware that the weather in the Algarve at Christmas can be relatively cool (+-10ºC to 15ºC), windy and wet.
In winter, you may find that the Algarvean towns of Lagos or Albufeira more suitable destinations. Alternatively, Xmas may be a good time to visit the capital of Portugal, Lisbon. It is only +-3hrs by train from Faro and there will certainly be more to do there.