Generate New Query Offsets
To generate new query offsets:
On the Time Zone IDs page, click the Generate Query Offsets button.
Enter start and end dates for the time range to generate, for instance, 1/1/2009 to 1/1/2011, and click OK.
This updates the time zone offset table (PSTZOFFSET) to reflect the current time zone and DST definitions. This data can be re-generated as needed.
See the additional time zone documentation available on My Oracle Support.