My idea for the planet the story is mostly set on is that the terraforming process was begun about 150 years ago and progressed far enough for the colonists to leave their environmental dome about 100 ago, but it's still a difficult environment. Since the planet gets less sun and has a thinner atmosphere than Earth people can only live comfortably and grow food outdoors around the equator - go much north or south, and it's comparable to the polar regions here. Survivable, if you have the proper equipment, but no place most people would consider visiting for fun.
Does this seem like a reasonable pattern? I have scientific training, but climatology was definitely not my focus. Thanks!