- date: documentation ( source)
<?php
$tz = new DateTimeZone('America/New_York');
$ts = 1414907940;
$d = date('Y-m-d H:i:s', $ts);
$dt = new DateTime();
$dt->setTimezone($tz);
$dt->setTimestamp($ts);
$di = new DateInterval('PT1M');
$dt->add($di);
echo ($dt->getTimestamp() - $ts); // expecting 60