June has been the Month of the Sacred Heart ever since the feast was instituted in the 19th century.
In popular piety, each month of the year has a corresponding spiritual theme that focuses on various aspects of the Christian faith.
June has become known as the Month of the Sacred Heart, due to the fact that the feast of the Sacred Heart is celebrated each year during it.
It all started when St. Margaret Mary Alacoque received private revelations from Jesus Christ.
Jesus spoke to her on June 16, 1675, and asked her specifically to promote a feast that honored his Sacred Heart.
I ask of you that the Friday after the Octave of Corpus Christi be set apart for a special Feast to honor My Heart, by communicating on that day, and making reparation to It by a solemn act, in order to make amends for the indignities which It has received during the time It has been exposed on the altars. I promise you that My Heart shall expand Itself to shed in abundance the influence of Its Divine Love upon those who shall thus honor It, and cause It to be honored.
The feast of Corpus Christi has been celebrated after Trinity Sunday for many centuries and always falls during the month of June.
The precise date fluctuates each year, as it is determined by the celebration of Easter.
It took until 1856 for the feast of the Sacred Heart to be officially celebrated by the universal Church, and ever since then the month of June has been focused on devotion to the Heart of Jesus and his divine love for humanity.