<?php
function get_month_name($month)
{
 return date("F", strtotime(date("d-$month-y")));
}
$dates = date("Y-m-d");//replace your dates
$date = explode('-', $dates);
$monName = get_month_name($date[1]);
echo $monName;
?>
In above example it prints the current month name 'June'.