PHP Time Zone Fix

We have 4 web pages that are all synced together to allow people to register for events. Right now, the time zones are not consistent on each page. We have our server setup on Central time and then we used the php code: date_default_timezone_set('America/Los_Angeles'); We used that code to change the timezone to LA time. However, the pages display different times. You may see one of the pages below: [login to view URL] (this is wordpress and the time is in the sidebar) Another page is here: [login to view URL] The 2nd page is setup in Smarty - however that shouldn't make a difference as all the issues are in PHP side of the programming. Senior PHP Developer is available on our team to ask question. This should be a 1 hour project for someone who understands time zone PHP well.