- var_dump: documentation ( source)
<?php
$userTimezone = new DateTimeZone('Europe/Chisinau');
$from = new DateTime( 'now' );
$from->modify( 'first day of this month' );
$from->setTime(0,0,0);
// $from->setTimezone( new DateTimeZone( 'UTC' ) );
$from2 = clone $from;
$mongoTime = $from2->getTimestamp();
var_dump($from->format('Y-m-d H:i:s'), $from2->format('Y-m-d H:i:s'));