I'd just write a simple routine to do it. Something like the following wouldn't be awful, in a dozen lines of code or so: 
sub days_in_month {
    my $month = shift;
    my $year = shift;
    my @mdays = qw( 31 28 31 30 31 30 31 31 30 31 30 31 );

    if ($month == 2) {
        if ($year % 4 == 0) {    # normal leap year
            if ($year % 100 == 0) { # century year, not a leap year
                return 28 unless 
                ($year % 400 == 0); # century AND leap year
            }
        return 29;
        }
    }
    return $mdays[$month - 1];    # fudge the index
}

[download]

Update: Foggy and Adam contributed the current state of (now tested) not-so-bugginess. Seems like I should have actually *looked it up* in my library before I tried to recreate this wheel from memory.

I originally intended this to be straightforward teaching code, but Adam's second snippet is much better.

In reply to RE: simple stupid time question by chromatic
in thread simple stupid time question by lindex

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