A new and distinct cultivar of Dendranthema plant named ‘Sundance Igloo’, characterized by its upright, outwardly spreading and uniformly mounded plant habit; freely branching habit; dense and full plant form; uniform and freely flowering habit; daisy-type inflorescences; bright yellow-colored ray florets; natural season flowering occurs about September 14 to 24 in Pennsylvania; and good garden performance and winter hardiness.