The calendar that I post on Lexorandi lists the Ember Days for each of the four seasons.
It seems that changes made to the Roman Breviary in the 1960 revisions regards the arrangement of the months from August to November. This seems to have some effect upon their determination of the dates of the September Ember Days.
This year Ember Wednesday is September 22, Ember Friday is September 24, and Ember Saturday is September 25.
By clicking on the title above you can read the entire article on The New Liturgical Movement.