Find day of week in date range.

find_day_of_week.php

<?php
$start_date = new DateTime('2014-07-01'); // Create Start Date
$end_date = new DateTime('2014-07-31');  // Create End Date
$interval = DateInterval::createFromDateString('1 day');
$period = new DatePeriod($start_date , $interval, $end_date);
$day_of_week = array();

foreach ($period as $dt)
{
    $day_of_week[] = $dt->format("N");
}
?>