Bauchan of the Raith Sidhe is Jupiter's father
In the prologue of The Alchymist's Cat, Imelza encounters a mysterious black cat who seduces her and becomes the father to her litter of kittens. He is very evasive when she tries to question him about who he is, but one of the things he does say is "This night is the first I have seen with these eyes." The black cat tells her he has many names, more than she could guess, and that she may call him Imp. Bauchan is the trickster of the Raith Sidhe, who can take on any form he likes. If Bauchan is indeed the father of Jupiter, it is ironic as the Raith Sidhe are later overthrown by the latter when he rises to power as a living god in the sewers. The events of the Deptford Mice trilogy took place in 1981
In The Deptford Mice Almanack, the Great Oak wherein the spirit of Hobb is imprisoned topples over during heavy rains. This is a real tree
in Greenwich Park, and it did fall during a storm in 1991. As The Deptford Mice Almanack is supposed to take place ten years after The Final Reckoning, that would put the events of the latter (and preceding books) around the year 1981.