Italy has not (and has never had) a met office. We are 3rd world country in the political organization of meteorology.
When it was decided to create the WMO, the panorama was
1) lots of hydro-meteo stations, that were (most of them) intended for urban monitoring and hydrological purposes.
2) a few weather stations in airports, operated by military air forces (Aeronautica Militare, A.M.).
At that time the Government decided to join WMO and to assign to AM the task of representing Italy inside it. In my opinion this depends mainly on the fact that mils were embedded in networks of international relations, plus they had some experience of forecasting, plus perhaps some of them also spoke English.
AM operates its small group of stations and some of the stations they use are not operated by them but by a company for the organization of civil aviation, named ENAV (total AM+ENAV about 110-120 stations), most in airports. AM handles and list only its own stations and the ENAV ones, that are the only Italian stations having a WMO Id (there is also a WMO station non-AM/non-ENAV, it is Rome-Collegio Romano, operated by UCEA, the typical old observatory without practical interest because of UHI affection and bad and unrepresentative location -urban station in the top of a tower- but antique and prestigious because of its history)
Next to AM, most if not all regions have developed their own network of weather stations and local forecasting service, with appreciable problems of standardization between regions. Most of the stations are excellent automated ones with full instrumentation complying WMO standards and installed and maintained according to WMO guidelines, but some are not and sometimes it is difficult to evaluate the reported values because when one emails to ask, the answer is not 100% sure.
In my opinion, most temperature values of Italian stations non-AM/non-ENAV are reliable given they were measured after 1991-1992, when most of meteo-wreckage manned stations with Stevenson shelter were swept away and replaced with WMO compliant suburban-rural automated stations with multiplates shelters. AM/ENAV stations are most of the times still manned with Stevenson shelter, so I am very prudent with them. It is former Soviet Union Republics-rank technology.
About Catenanuova, I am prudent about its +48,5. Some believe it 100% but I am more prudent about. At that time several other stations hit >=47°C and this seems to support that 48,5°C. The main problem is that the organization operating the station does not show any interest for records etcetera and is not publishing anything about. However there are the data pages, there are emails of Osservatorio delle Acque executives saying that the station was OK and the temperature is OK. I do not know what to say. These are the documented things. The statements that appeared in Wikipedia some months ago about a failed recognition by WMO because of noncompliance with WMO standards were lies (the editor was never able to present references for these statements he had invented), deliberate misinformation that was disseminated in order to discredit Catenanuova's +48,5°C.