//PHP Version 5.3.0
date_default_timezone_set('Asia/Jakarta');
//date 2012-01-30 00:00:00
$timestamp = mktime(0,0,0,30,1,2012);
echo date('Y-m-d H:i:s',$timestamp);

This is strange, timestamp from this date 30 Jan 2012 doesn't output the same date from mktime

mktime bug, Date Output doesn't same with the input

PHP