A folk calendar is the crystallized wisdom of former people’s empirical standards, as well as a conscious understanding of time. With regard to the content of Russian folk calendars, they record seasonal folk customs, agricultural events, labor technologies, and changes in nature through short writings like proverbs, climate signs, and exhortations on taboos. As for their structure and form, they accept the time units of the orthodox calendars of the church (year, month, day, holiday, commemorative day). The primary naming principle is to take a Christian saint’s name to be the designation for a season. For instance, in the calendar of the Church, May 18 commemorates St. Irene, the Great Martyr of Thessaloniki. However, in the folk calendar, this day is known as “Irene, the Girl who Transplants Cabbage Seedlings;” it became a day when women planted cabbage seedlings. The relationship between the original name Irene and its indications gradually drifted apart, and attained its new semantic association with the date May 18. As time went by, the connection between to the name Irene and a saint gradually faded from memory amongst people, who didn’t remember the past deeds of this devout Christian or her history of ascetic practice. Rather, people have a direct association with the natural phenomena of this spring day, folk myths and folklore, taboo rituals, etc. In this paper, I wish to begin the discussion from the historical development of the Russian calendar, then explore the characteristics of the Eastern Orthodox Christian Church’s calendar. Following, I study Russians’ views of seasons and holidays and explore in depth the structure of folk calendars and the principles of naming calendrical units. From the perspectives of folklore studies and anthroponomy, I investigate how the names of Christian saints transformed from the church calendar to the folk calendar. These various kinds of changes, which occurred as a reaction to the demands of people’s lives, serve as a point of entry to scrutinize the subject of the folk calendar.