A female apparition sometimes encountered on snowy nights, usually described as having white hair or skin, being cold to the touch, or otherwise being similar to the frigid winter landscape.

A early description of the snow woman is found in the Sōgi Shokoku Monogatari (宗祇諸国物語, c. 1690). The author describes an experience in which he caught sight of a strange woman on the edge of a bamboo grove, about twenty years of age, wearing a white unlined kimono and with skin so pale as to be transparent, and a full jō (~10 ft/3.3m) in height.

Although she is often thought to come out during snowstorms or during a full moon, in some regions the snow woman is said to make her appearance on a fixed date. In Iwate Prefecture's Tōno area she appears on koshōgatsu (January 15th), and in Aomori Prefecture's Nishitsugaru District she shows up on New Year's Day and leaves on the first day of February.

The yuki-onna is considered the spirit of the snow itself, or perhaps the ghost of a woman who died in a snowstorm, but according to one source, the yuki-jorō of the Oguni area of Yamagata Prefecture is believed to have originally been a princess of the moon. Tiring of life in the heavens, this lunar maiden descended on a snowfall to investigate the earth, only to discover she could no longer return to the sky. She still appears on moonlit nights when the snow is deep.

Although she may have originated as a heavenly being, this same yuki-jorō is considered to be an abductor of children, and she always has a great number of her adopted brood with her. The snow woman is often used to admonish children who stay out too long after dark or who cry at night, as this chilly surrogate mother will surely find them and spirit them away.

Other yuki-onna are even more menacing; the snow woman of Niigata Prefecture causes people to freeze to death and tears the livers out of living children, in Iwate and Miyagi she can pull out your soul, and in Ibaraki she calls out to passers-by and pushes them into ravines if she is ignored. In Aomori she takes on the character of the mother ghost called ubume, harassing people into holding her child, which then becomes so large as to crush the bearer.

Citations:
1. Murakami 2000 p. 356, Murakami 2005 p. 348, Inada p. 67, Tada 2000 p. 168. The original source for the story of the moon princess who became the yama-jorō is the Uzen Oguni Gō no Denshō (羽前小国郷の伝承, Folklore from the Countryside of Oguni in Uzen)