echo date("m", strtotime("january"));

echo date("m", strtotime("february"));

echo date("m", strtotime("February 1"));

function getMonth($month, $leadingZero = true) {
    $month = strtolower(trim($month)); // Normalize

    $months = array('january' => '1',
                    'february' => '2',
                    'march' => '3',
                    'april' => '4',
                    'may' => '5',
                    'june' => '6',
                    'july' => '7',
                    'august' => '8',
                    'september' => '9',
                    'october' => '10',
                    'november' => '11',
                    'december' => '12',
                    'dezember' => '12', // German abrevation
                    'marts' => '3', // Danish abrevation for March
                   );

    if(isset($months[$month])) {
        return $leadingZero ? substr('0' . $months[$month], -2) : $months[$month];
    } else {
        return false;
    }
}