PHP strtotime for June returns July
===

I'm stumped as to why the following PHP strtotime function returns '07' as the month number, rather than '06' when $monthToGet = 'June':

    $monthToGet = $_GET['mon'];
    $monthAsNumber = date('m', strtotime($monthToGet));

From searching, it appears it may be due to default date parameters (in this case the day and year) as I haven't specified them. Would that be the cause?

Any suggestions appreciated!