z/OS set timezone and manage daylight saving time (DST)

In z/OS > 1.8 you can use the MVS SET TIMEZONE command to set a new time for displaying entries (internal date is unchanged) and doesn't need an IPL.
We can use that for the daysaving hour change.

The first is change the SYS1.PARMLIB.CLOCK*XX* TIMEZONE value.

  OPERATOR NOPROMPT
  TIMEZONE W.12.00.00
  ETRMODE  YES
  ETRZONE  YES
  STPMODE  YES
  STPZONE  YES
  TIMEDELTA 10

TIMEZONE W.XX -> From Greenwich to WEST
TIMEZONE E.XX -> From Greenwich to EAST

Take that on mind if the change is +1 or -1 hour. The next one is apply the new setting in the working system.

To do that set the same timezone with this MVS command:

  T TIMEZONE=W.12

Later, we must made the change on OMVS: Edit /etc/profile and /etc/init.options files and set TZ=CST13PDT (for example)