A Hat Full of Sky
Miss Tick has arranged for Tiffany to work for a witch, to learn the tricks of the trade. (Her parents are assured she's being hired for her skill in cheese making.) Roland, the Baron's son, is awkward and infatuated when she leaves. The Nac Mac Feegle have acquired a normal kelda, Jeannie, who married Rob Anybody and does not entirely approve of Tiffany. Hag of the hills or no, after all, she was their acting kelda and engaged to Rob for a time.
Miss Level, in fact, is one person with two bodies. Indeed, she traveled with the circus as twins with a mind-reading trick before she became a witch. And Tiffany meets the other young girls who are training to be witches -- awkward young Petulia, and the haughty Annagramma who's learning "high magic" from Mrs. Earwig (pronounced "Ah-widge"). The Witch Trials are coming -- think Sheepdog Trials, actually.
And Tiffany has attracted the attention of a hiver. An unintelligent and very dangerous creature.
The story unfolds involving a foolish wizard at the Unseen University; the pig trick done with sausage; Oswald, who likes to tidy things; Jeannie putting a geas on Rob Anybody, milking goats, a gift of a dictionary, dealing with Death, and much more.
The opening of this one is weak. Flashing back from a future scene is sometimes a good technique, but telling us it might not happen, without making it a dream or something, is weak.
Tiffany has switched witches, and is learning with Miss Treason, who's very old and Borrows the eyes and ears of creatures about her, and is famous for her ability to adjudicate cases. Tiffany makes cheeses (one of whom, Horace, is very lively) and writes to Roland, who writes back despite his horrible aunts and his ailing father.
But then Miss Treason takes her to see the Dark Morris, and she foolishly, against what she was told, throws herself into the dance. And the Wintersmith, the Anthropomorphic Personification of Winter, sees her, takes her for the Summer Lady, and falls in love. He doesn't have a good grasp on what humanity is.
Meanwhile life goes on, and Tiffany is also involved in a philosophical difference between witches that comes to a head over a witch's cottage.
It involves a clock, lots of snow, a Hero with a Sword, spelling marmalade, the underworld (as opposed to Hell), Tiffany's younger brother fishing, a children's rhyme, skulls, Explanations, and more.