In 1849, Pope Pius IX had assigned the feast of the Precious Blood of JESUS to be celebrated on the first Sunday after June 30, the anniversary of the liberation of the city of Rome from insurgents.

In the changes he introduced to reduce the number of feasts fixed for Sundays, Pope Pius X fixed its date on July 1.

In 1933, Pope Pius XI raised the feast to the rank 1st Class to mark the 1,900th anniversary of JESUS's death.

In 1969, The feast was removed from the General Roman Calendar, "because the Most Precious Blood of Christ the Redeemer is already venerated in the solemnities of the Passion, of Corpus Christi, of the Sacred Heart of Jesus, and in the feast of the Exaltation of the Holy Cross. But the Mass of the Most Precious Blood of Our Lord Jesus Christ is placed among the votive Masses". {Calendarium Romanum (Libreria Editrice Vaticana 1969), p. 128}

The feast nonetheless continues to be celebrated as a solemnity in calendars of some religious orders such as the Missionaries of the Precious Blood, the Congregation of the Passion of JESUS CHRIST, and the Adorers of the Blood of CHRIST. Furthermore, it is celebrated by parishes and communities that observe the 1962 Calendar. 

It is also traditionally celebrated in the Holy Land on July 1 at the Basilica of the Agony in Gethsemane. MORE

The whole MONTH of JULY is still kept dedicated to the Most Precious Blood.