To get a list of possible time_zone values in your MySQL server instance, use this command.
Unix-like operating systems (Linux distributions, BSD distributions, and modern Mac OS distributions, for example) receive routine updates. Installing these updates on an operating system lets the MySQL instances running there track the changes in time zone and daylight / standard time changeovers.
If you get a much shorter list of time zone names, your server is either incompletely configured or running on Windows. Here are instructions for your server administrator to install and maintain the ZoneInfo list.