gistfile1.txt

root@ckwalsh:~# cat foo.php 
<?php

$tz = new DateTimeZone('America/Los_Angeles');
$dt = new DateTime(null, $tz);

var_dump($tz);
var_dump($dt);
root@ckwalsh:~# php foo.php 
object(DateTimeZone)#1 (2) {
  ["timezone_type"]=>
  int(3)
  ["timezone"]=>
  string(19) "America/Los_Angeles"
}
object(DateTime)#2 (3) {
  ["date"]=>
  string(19) "2014-03-01 13:01:25"
  ["timezone_type"]=>
  int(3)
  ["timezone"]=>
  string(19) "America/Los_Angeles"
}
root@ckwalsh:~# hhvm foo.php 
HipHop Strict Warning: It is not safe to rely on the system's timezone settings. Please use the date.timezone setting, the TZ environment variable or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected 'America/New_York' for 'EST/-5.0/no DST' instead in /root/foo.php on line 4
object(DateTimeZone)#1 (0) {
}
object(DateTime)#2 (0) {
}
root@ckwalsh:~#