The practice of bathing in a consecrated ice-hole on the feast of the Epiphany is very common in modern Russia. Many people try to follow this tradition, each year coming to open bodies of water for the purpose of dipping in holy water.
First of all, it is worth noting that those who want to plunge into the blessed baptismal hole (in holy water) should resort to such a practice not immediately after 12 o'clock at night on January 19th, but only after the blessing of the water in the font. Otherwise, the person "dives" into ordinary water. The rite of consecration of the springs is held at different times. It is quite possible that some clergymen (especially in large cities), thanks to the large number of clergy, consecrate the fonts ("Jordan") at about midnight. However, these cases are not so common in modern practice.
Most often, fonts are consecrated after the night festive divine service in the morning. In some churches, the liturgy for the feast of the Baptism of the Lord is celebrated not on the night of January 19th, but in the morning of the same date. In such cases, the springs may be blessed at night before the liturgy. Thus, depending on the time of the consecration of the font, it is necessary to count down the correct time for immersion in Jordan.
It is worth noting that it is customary to swim at consecrated springs during the astronomical day on January 19 (exactly on the very day of the Baptism of the Lord Jesus Christ). With the onset of January 20th (starting at 12 o'clock at night), bathing in the fonts stops. Nowadays, it is already quite difficult to meet people who plunge into the ice hole after the 19th of the second winter month.