Magic
The Celestial Convergence
A night when the winter stars stand at their brightest — and the night the story begins.
A Celestial Convergence is an alignment with recognised influence on temporal magic; it is a documented subject of study, with texts devoted to it.
On the Convergence in question the winter stars stand at their brightest. Amara Zephyr suggests closing the shop early, and her pendant begins to pulse before she can finish the thought.
In the books
This is established in The Awakening, book 1 of The Arcane Odyssey.
Explore The Awakening