date - How do I find what day the last saturday of the current month is in PHP?

Question

This works for most months, but for example, April 2011 has 5 saturdays, so this returns 23 instead of 30.

$last_saturday = date("j", strtotime('Fourth Saturday'.date('F o')));

Answer 1

Interestingly enough, strtotime("last saturday of this month") does exactly that.

See Supported Date and Time Formats for more, particularly the section on Relative Formats.