According to the folk calendar - Fyodor Studite, Fyodor Moroz

November 24 is the day of remembrance of Fyodor the Studite, a Byzantine monk, preacher of Christianity, prominent church figure, and ascetic. His nickname “Studit”, which he received while managing the Studite monastery, was misinterpreted in Rus'. Memorial Day coincided with the beginning of the winter cold, so the monk began to be called Fyodor Moroz. A proverb appeared among the people: “Fedor Chills the earth,” and with the inevitable onset of winter, people added to it: “With Studit, the cold is worse every day.” Signs of the weather: if it was wet snow on Fedor Studit, then winter receded until the end of December and the weather remained warm for a whole month.