IANA Time Zone vs CET / CEST
Europe/Rome is the primary location-based identifier for Italy. It represents real transition rules across dates. CET and CEST are human-readable seasonal abbreviations and should not replace a location-based identifier in date-aware software.
Do Sicily or Sardinia Use a Different Time Zone?
No. Italy’s two largest islands use the same national clock as the mainland. Palermo, Catania and the rest of Sicily, as well as Cagliari and the rest of Sardinia, change between CET and CEST at the same instant as Rome, Milan, Venice and Naples.
Mainland ItalyEurope/Rome · CET/CEST.
SicilySame CET/CEST schedule as mainland Italy.
SardiniaSame CET/CEST schedule as mainland Italy.
Best practiceUse Europe/Rome and calculate the offset for the actual date rather than hardcoding UTC+1 or UTC+2.