- strtotime: documentation ( source)
<?php
$dates = array("24-12-2013","25-12-2013","26-12-2014","27-12-2013");
$start = strtotime('25-12-2013');
$end = strtotime('26-12-2013');
foreach($dates AS $date) {
$timestamp = strtotime($date);
if($timestamp >= $start && $timestamp <= $end) {
echo "The date $date is within our date range\n";
}
}