November / December are the best months in these waters.
I never surfed around Rome, but I guess you will find mostly short period waves, due to the short fetch (Corsica and Sardinia are blocking the quality swells coming from spain).
I heard it is quite crowded and water quality is bad near the city, I guess you should try to move away from it as much as possible.
A good wave forecast site is:
www.ilmeteo.it/portale/node/68/-10Non-secret spots can be found at
www.wannasurf.com/spot/Europe/Italy/Mainland/index.html