https://catholicgentleman.com/2022/12/ember-days-101/There are four “sets” of Ember Days during the year. Each “set” is a successive Wednesday, Friday and Saturday. They occur every year near the beginning of the four seasons.
Spring: after Ash Wednesday.
Summer: after Pentecost Sunday.
Fall: after Sept. 14, the Feast of the Exaltation of the Holy Cross.
Winter: after Dec. 13, the Feast of St. Lucy.
A traditional way of remembering these dates is the rhyme “Lenty, Penty, Crucy, Lucy”