The Water Cycle: (I grabbed the idea of a huge rise and fall from the Dragonmech supplement that I like it so much and created the “mechanics” for it and welded it to my version of Áereth.)
Other than the wild celestial displays, there are a couple of other notable features of my version of Áereth that makes her unique. Both of which have to do with the oceans. Firstly, the surface of Áereth is 80% water. The maps provided of the continents represent the largest land masses on the planet. The rest of the available land mass is broken up into hundreds of thousands of small islands. Secondly, because of the axial tilt and her orbital mechanics, there is a huge seasonal variance in the ice cap at the South Pole. There are complicated mechanics, but the short of it means that ocean levels drop at 2.747ft per day (for 182 days) until the peak of ice formation when the whole process reverses itself as the sun and ocean currents eat away at the ice shelf. The ocean levels differ by 500ft between “High-water” (Winter Solstice in the North) & “Low-water” (Summer Solstice in the North), then the process reverses itself. This means that the coastlines of Áereth are everything from awe-inspiring cliffs to huge inter tidal mud flats that can be wider than a hundred miles[ linking up many islands. All Maps are drawn from the perspective of High-water in the northern hemisphere.
The fallout from this part of the design process was the birth of two vastly enlarged ecological zones: tidal flats & ice flow. They are a lot of fun... As the water goes out, a sea of salt resistant grass sprouts in its wake; by "mid water" [Spring Equinox] the grass has grown taller than a humanoid on a horse. The creatures that live "out on the flats" take advantage of the wandering herds of herbivores migrating into the new grasslands... By mid-summer the water has turned around and begins its long trek back to High-water; bringing hoards of very hungry ocean dwellers along for the ride.
The First wave of these ocean dwellers are the herbivores and bottom feeders dealing with the dieing grass and detritus. Followed by the next waves of free swimming hunters... each bigger than the last as the water gets deeper. In some places the returning water also brings with it huge floating sheets of ice drifting along; many large enough to house whole tribes of humanoids. Some species and cultures depend on the ice break up to deliver them to new feeding grounds on the warmer main lands; only to return to the ice and start the process all over again.