This is a list of time zones from release of the tz database.
Offsets of Standard Time (SDT) and Daylight Saving Time (DST) from UTC are noted in hours and minutes.
For zones in which Daylight Saving is not observed, the DST offset shown in this table is a simple duplication of the SDT offset.
The offsets from UTC are based on the current or upcoming database rules. This table does not attempt to document any of the historical data which resides in the database.
In Ireland, what Irish law designates as "standard time" is observed during the summer, with clocks turned one hour ahead of UTC. The SDT column shows the offset from UTC during the winter, even in Ireland, where that's referred to as "winter time", and the DST column shows the offset from UTC during the summer, even in Ireland, where that's referred to as "standard time".
Time zone abbreviations for both Standard Time and Daylight Saving Time are shown exactly as they appear in the database. See strftime and its %Z field. <br>Some zone records use three- or four-letter abbreviations that are tied to physical time zones; others use numeric UTC offsets.
In Ireland, what Irish law designates as "standard time" is observed during the summer, with clocks turned one hour ahead of UTC. The SDT column shows the abbreviation used during the winter, even in Ireland, and the DST column shows the abbreviation used during the summer, which is IST, where the S in IST stands for Standard, not Summer.
Legend: