"It is the Washin' o' the World's Face."
(R. García y Robertson, The Spiral Dance)
Our story so far: The Chinese have invaded America and then (for reasons never specified) pulled out again. The East Coast literally walls itself off from the rest of the Continent and becomes a stuck-in-the-head techno-megalopolis.
Meanwhile, the rest of the Continent reverts to tribalism. Foremost among these tribes are the Latter-Day Witches who call themselves "Circle", or "Coven", who through centuries of inbreeding have achieved mastery of the art of direct mind-to-mind communication, what they call lep.
(If you suspect that this has something to do with telepathy, I think you're probably right.)
That's the universe of Marvin Kaye and Parke Godwin's Masters of Solitude series, some of the earliest (late 70s/early 80s) popular literature to be profoundly shaped by the emerging Wiccan movement.
Being, in effect, our children, the people of Circle observe the same Wheel of the Year that we do today. Part of the fun of the novels for pagans lies in extricating the names of the firedays from what 1000 years' worth of linguistic erosion have left of them.
For Circle folk, Eostre/Ostara/Easter is Leddy. (I myself can remember back when, in the early days of American paganism, some folks knew Spring Equinox as Lady Day.) Then comes Belten, Sinjin (< “Saint John['s Day]"), Lams, Milemas ( < Michaelmas), Samman, and Loomin for Yule. (I'm guessing that this latter is probably a worn-down form of illumine, drawn perhaps from Doreen Valiente's quintessential Yule chant Queen of the Moon, Queen of the Sun: "Golden Sun of the Mountains,/Illumine the Land, Light up the World,/Illumine the Seas and the Rivers,/Sorrows be laid, Joy to the World." If so, it's a nicely folkloric touch.)
Their Imbolg/Oimelc/Candlemas is Grannog.