The Church has for centuries dedicated the month of May and October to the Blessed Virgin Mary.  At first it might seem a little weird for the Church to dedicate a month to a person but dedicating a specific amount a time, a day, a month, a year is actually a very normal human thing to do.  In fact we do it all the time, when we celebrate birthdays, anniversaries, etc.  We use this idea of setting aside time as a reminder of sorts to celebrate our relationship with a person or in some cases like Independence Day an institution.  It is kind of a fool proof way (unless one forgets or ignores the dedication) to make sure that at least once a year we take the time not only to remember the person but also to celebrate that person.