Yes, it was Christmas in June as the Catholic Church celebrated the Solemnity of the Nativity of St. John the Baptist on 24th June (Yesterday) which is the commemoration of the birth of Jesus’ cousin, John.
St. John’s birthday is celebrated every June 24, which is three months after the Annunciation and six months prior to the birth of Christ. The feast in a way, coincides with the summer solstice, which is the time of the year when the days are the longest.
But immediately after the celebration of St. John’s birthday the days become progressively shorter up till the winter solstice around December 25 when the days start to get longer again. This actually corresponds to the words of St. John the Baptist, “He must increase, but I must decrease.”
Based on history, Christians would celebrate this day in a very similar way to Christmas. The Catholic Encyclopedia goes explains the extent to which medieval Christians connected the two feasts.
The resemblance of the feast of St. John with that of Christmas was carried more far, for another feature of the 24th of June was the celebration of three Masses which are: the first, in the dead of night, which recalled his mission of Precursor; the second, at daybreak, which commemorated the baptism he conferred; and the third, which at the hour of Terce, honored his sanctity.
The whole liturgy of the day, which is repeatedly enriched by the additions of several popes, was in suggestiveness and beauty on an equal value with the liturgy of Christmas.
So, St. John’s day was so sacred that it was deemed that two rival armies, meeting face to face on 23 June, by common accord put off the battle until the morning of the feast (Battle of Fontenay, 841).
In 506, the Council of Agde, listed the Nativity of Saint John among the highest feasts of the year, it was a day on which all faithful had to attend Mass and abstain from servile work.
Indeed, the rank of this festival was so great that, just as on Christmas, three Masses were celebrated, one is during the vigil service, the second at dawn, then the third in the morning.
In the year 1022, a synod at Seligenstadt, Germany, mandated a fourteen-day fast and abstinence in preparation for the Feast of the Baptist.
Many Eastern Christians however, maintain some of these traditions, such as an all-night vigil which precedes June 24.
So, in many ways the feast of St. John the Baptist gets us ready for the celebration of Christmas, and even though it is summer in the Northern Hemisphere, June 24 goes forth to give us a hint of what’s to come in December!