The documentation, section 18.104.22.168 Requirements for Creating Standing Reservations (UG-139, or page 1685 of the big book), states that
You must set the submission host’s PBS_TZID environment variable. The format for PBS_TZID is a timezone location. Example: America/Los_Angeles, America/Detroit, Europe/Berlin, Asia/Calcutta. See section 1.4.5, “Setting Time Zone for Submission Host”, on page 10.
Does this mean that PBS doesn’t honour the timezone setting in the OS itself?