America/Argentina/Buenos_Aires

TZ identifier and aliases

America/Argentina/Buenos_Aires is the canonical identifier for Argentina Time. The shorter America/Buenos_Aires is an older name still pointing at the same rules but is a deprecated alias — use the full America/Argentina/Buenos_Aires form in new code. A long list of Argentine provincial capitals — America/Argentina/Cordoba, America/Argentina/Mendoza, America/Argentina/Salta, America/Argentina/Tucuman and others — currently share identical rules and are folded into the same entry, a legacy of Argentina's historically fragmented, province-by-province approach to daylight saving.

UTC offset and DST rule

America/Argentina/Buenos_Aires is -03:00 year-round with no daylight saving time. Argentina's last DST experiment ended in 2009; since then the whole country, not just Buenos Aires, has kept a single fixed offset.

Using it in cron, CI and Postgres

Set TZ=America/Argentina/Buenos_Aires for a process that should schedule by Argentine local time — the full path matters here specifically because the shorter America/Buenos_Aires alias is deprecated and some minimal tzdata builds (certain Alpine Docker images, for instance) may omit legacy aliases entirely, so relying on the canonical form avoids a missing-timezone error in a stripped-down container. Postgres accepts it via SET TIME ZONE 'America/Argentina/Buenos_Aires'; or the timezone setting. Because the offset never changes, a cron job's local-time schedule behaves identically every day of the year, with no DST boundary to work around.

History and quirks

Argentina's relationship with daylight saving has been unusually inconsistent by South American standards: the country used biannual clock changes from 1920 to 1969, dropped the practice, briefly revived it for the 2007–2008 season, and abandoned it again in 2009 — while different provinces occasionally set their own local rules independently of the federal government during the more chaotic periods, which is the root cause of the tz database's long list of province-specific Argentine zone names even though nearly all of them are rule-identical today. At -03:00, Buenos Aires sits only two hours behind most of Western Europe in winter, a relatively easy gap for business collaboration, but that gap widens to three or four hours once Europe's DST kicks in each spring, since Argentina itself no longer shifts to compensate.

That long alias list is a genuine legacy of federalism rather than a data artifact: during the 2007–2008 revival specifically, a handful of provinces opted out or applied the change on different dates than Buenos Aires, prompting the tz database maintainers to give each province its own named zone so historical timestamps from that period could still be resolved accurately. All of those entries have shared identical rules since the 2009 rollback, which is why modern tooling treats America/Argentina/Buenos_Aires as representative of the whole country — but the separate historical entries remain in the database specifically to keep old, province-specific timestamps computing correctly rather than being silently reinterpreted under today's unified rule.

Offsets and DST transitions on this page are computed from the IANA time zone database bundled with your browser; the rules described above were verified against tzdata 2026b when this page was published.