- var_dump: documentation ( source)
<?php
$tz = new DateTimeZone('-09:00');
$dbTz = new DateTimeZone('+00:00');
$date = new DateTime('2015-08-31T15:00:00-09:00', $tz);
var_dump($date);
/*
$date = $date->setTimezone($tz);
var_dump($date);
*/
$date = $date->setTimezone($dbTz);
var_dump($date);