According to the folk calendar - Epiphany, Holy Epiphany

On January 19 (January 6, old style), according to the popular calendar, Epiphany is celebrated, also called Holy Epiphany. According to biblical tradition, on this date the baptism of the son of the Most Holy Theotokos and the Lord, Jesus Christ, took place. There were usually severe frosts at Epiphany. The day before, people kept a one-day fast, and at dawn they went to a reservoir and made a hole in the ice in the shape of a cross. The village priest read a prayer service and lowered a cross into the hole, after which the water was considered blessed. The peasants believed that such water had healing properties and helped against various ills. Everyone took water from the reservoir and carried it home. According to legend, the one who first took the baptized water was healthy for a year. The faster they brought it home, the more the land yielded. And the one who spilled the water or fell with it was overtaken by misfortune. Blessed water could be stored for a year without spoiling. They washed themselves with it, splashed it on sore spots, sprinkled the house in the corners so that evil spirits would not enter. They also drank it themselves for better health and poured it into livestock so that they would not get sick and would have more fruit. Christmas time ended at Epiphany, and New Year's decorations for the house were put away until next year. From Christmas to the eve of Epiphany, fortune-telling was performed, which was considered a sinful act in the church. To remove sin from oneself, one had to plunge into the blessed water of a frozen reservoir three times. This is where the tradition of swimming in the ice hole on this day came from. By signs on Epiphany holidays they learned about the future harvest. If there was a strong snowstorm, then the fields produced a lot of grain in the summer. The night with bright stars promised a rich harvest of forest berries and legumes. The dog's long barking foreshadowed an excellent hunt for animals and birds. If water seeped into an ice hole above the ice or fog shrouded the river, people expected the water to overflow its banks in the spring.