- var_dump: documentation ( source)
<?php
$todayStart = new \DateTime('today 0:00');
$todayStart->setTimezone(new \DateTimeZone('PST'));
$todayEnd = new \DateTime('tomorrow 0:00');
$todayEnd->setTimezone(new \DateTimeZone('PST'));
var_dump([$todayStart->getTimestamp(), $todayEnd->getTimestamp()]);