Cum laude means 'with honor', magna cum laude is 'with high
honor', and summa cum laude means 'with the greatest honor'. These
designations are granted to every graduate who meets a required
grade-point average, so several students in a class, or even an
entire class, could graduate cum laude, magna cum laude, or summa
cum laude. The valedictorian is the student with the highest
academic rank in the class, so you would expect he would at least
be a cum laude graduate. But if you have a class where no one has
over a B average, there will still be a valedictorian but he will
not be graduated with honors.