- date_default_timezone_set: documentation ( source)
<?php
date_default_timezone_set('Europe/Warsaw');
$today = new DateTime(1414285200);
echo $today->format('O') . " - today";
echo "\n";
$sunday = new DateTime('2014-10-26 02:00:00');
echo $sunday->format('O') . " - last Sunday 2:00 " . $sunday->getTimestamp();
echo "\n";
$sunday2 = new DateTime('2014-10-26 01:59:59');
echo $sunday2->format('O') . " - last Sunday 1:59 " . $sunday2->getTimestamp();
echo "\n";
echo $sunday->getTimestamp() - $sunday2->getTimestamp();