— Helen Green
At the latitude of Madison, the Ice Age worlds have a thick layer of dirty permafrost on top of the ground, meaning that you have to be elevated off the surface in neighbouring worlds to be able to step. There are no living things here.
At the latitude of Richmond, Virginia, the same worlds don't have much ice, though the ground is completely frozen. The sky is bright blue and cloudless, and there are sometimes blizzards here.
In other areas, the ground of the Ice Age worlds is covered in knee-deep snowfields.
Interglacial worlds, which are warmer than the Ice Age worlds, are full of animals. In North America there are huge herds of horses, antelopes, camels and cow-like creatures. There are also wolves, coyotes, elk, curlews, bears, snakes, rabbits, buffalos, apes and big armadillos. Birds include crows, ravens, turkey, buzzards, owls and ducks.
Some interglacial worlds are only slightly warmer than the Ice Age worlds. Bent-over dwarf trees exist on these worlds, as well as midges and huge deer. The ground is boggy.
Because some of the worlds of the Ice Belt have ice ages, people who travelled by foot like the Greens on their way to Earth West 101,754 had to take a detour to Richmond, to go south of the ice and be able to step. People travelling by twain don't have this problem since they fly above the ice.
The Greens traveled about a step a minute, for six hours every day (so around 360 worlds per day). In the first two days (so from Earth West 10 to approximately Earth West 730) the worlds were mostly interglacial, although there were a few Ice Age worlds. The interglacial worlds continued until the seventh day (around Earth West 2,500), when they hit the first sheaf of Ice Age worlds.