SQL & PL/SQL

Thanks to everyone who answered by previous question about SYSTIMESTAMP.

Here's a PL/SQL function I wrote to convert the current time to PST and return it as a DATE value. The idea is that it should work regardless of what the database's timezone is set to.

Any critiques are welcome - efficiency, style, whatever. In particular, is there a way to avoid the conversion to a VARCHAR2? Is there a system supplied function I am overlooking?

Thanks again!

CREATE OR REPLACE FUNCTION PST_SYSDATE RETURN DATE IS
  th NUMBER;
  tm NUMBER;
  now TIMESTAMP(6) WITH TIME ZONE;
  d  VARCHAR2(200);
BEGIN
  now := SYSTIMESTAMP;
  SELECT
    TO_CHAR(now, 'YYYY-MM-DD HH24:MI:SS'),
    EXTRACT(timezone_hour FROM now) TH,
    EXTRACT(timezone_minute FROM now) TM
  INTO d, th, tm
  FROM DUAL;
  
  RETURN TO_DATE(d, 'YYYY-MM-DD HH24:MI:SS') - ((th+tm/60+8)/24);  
END PST_SYSDATE;
/