Traditional calendars mark the Ember Days of the Quatuor Tempora recommended by the Church and usually have an explanation similar to the one below.
"Ember days are on the Wednesday, Friday, and Saturday following the First Sunday in Lent and after Pentecost Sunday, during the third full week of September and after the Third Sunday of Advent.
"They are days of fasting for the special sanctification of the four seasons and for obtaining God's blessing on the clergy, for whose ordination the Ember Saturdays are specially set apart."
"The Propers of the Mass reflect the Season in which they occur and include additional lessons said before the Gospel." (2018 Liturgical Calendar, The Seraphim Company, Inc.; Cf. TAN Saints Calendar).
Indeed, the universal liturgical law of the Church requires that every diocese publish calendars indicating the Rogation and Ember Days of the year and how to keep them!
"Each diocese should have its own Calendar and Proper of Masses. For its part, the Conference of Bishops should draw up a proper Calendar for the nation or, together with other Conferences, a Calendar for a wider territory, to be approved by the Apostolic See.
"In carrying out this task, to the greatest extent possible the Lord’s Day is to be preserved and safeguarded, as the primordial feast day, and hence other celebrations, unless they are truly of the greatest importance, should not have precedence over it. Care should likewise be taken that the liturgical year as revised by decree of the Second Vatican Council not be obscured by secondary elements.
"In the drawing up of the Calendar of a nation, the Rogation Days and Ember Days should be indicated (cf. no. 373), as well as the forms and texts for their celebration, and other special measures should also be kept in mind." General Instruction of the Roman Missal, USCCB, 2010, 394.
"In carrying out this task, to the greatest extent possible the Lord’s Day is to be preserved and safeguarded, as the primordial feast day, and hence other celebrations, unless they are truly of the greatest importance, should not have precedence over it. Care should likewise be taken that the liturgical year as revised by decree of the Second Vatican Council not be obscured by secondary elements.
"In the drawing up of the Calendar of a nation, the Rogation Days and Ember Days should be indicated (cf. no. 373), as well as the forms and texts for their celebration, and other special measures should also be kept in mind." General Instruction of the Roman Missal, USCCB, 2010, 394.
Since the bishops are largely negligent in this (who in today's Church has even so much as heard about Rogation Days, Ember Days?) it is up to the faithful to produce and disseminate and use such calendars, for the good of the Church.
