IANA Time Zone vs CET / CEST
Europe/Berlin is the primary location-based identifier for Germany. 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.
What About Europe/Busingen?
Büsingen am Hochrhein is a German enclave surrounded by Switzerland. The IANA database exposes Europe/Busingen for that locality, historically aligned with Swiss time rules. Today its clock still follows the same CET/CEST schedule as the rest of Germany, so travelers do not encounter a second current legal time there.
Most German locationsUse Europe/Berlin.
Büsingen am HochrheinSoftware may expose Europe/Busingen; current civil time still matches CET/CEST.
Do not hardcode CETA fixed abbreviation or UTC+1 offset can miss the summer-time phase.
Best practiceStore a location-based IANA identifier and calculate the offset for the actual date.