Colorado is half mountains, half plains. On the eastern plains, it's very much so like Kansas, flat & boring. You can actually see the mountains from the Kansas border, provided there's not that much pollution. The "Western Slope" is exactly that, mountainous almost all the way to the Utah border. But that's where Moab is, and that's pretty mountainous, too. Denver proper sits in a basin where the Platte River flows through it. That's why where one of my co-workers, who lives downtown Denver, is zone 6, but my area fluxes from zone 5 to zone 4. It sucks. And the wind out here is hellacious. The only time it's not breezy/windy is in the ... uh.. hmm.. thinking.. well, it's ALWAYS windy! :D
