Originally posted by The Wizard of Oz
Did you see my question about whether day length varies by season, or by latitude? Do the far North and far South have periods of perpetual day in Summer, and perpetual night in Winter? Vance said he'd leave that to you.
Presumably the North has polar day lengths and strong seasonal variation, while the South has equatorial day lengths and weak seasonal variation, as per the general principle that you should be able to base things on real-world equivalents rather than memorizing counterintuitive lore. How that dovetails with the movement of the sun is something of a headache; if we actually address it in the text, it'll probably boil down to "a spirit court did it."