Sorry for the dig -- as a historic preservation buff, I quite enjoyed exploring the St. Louis Union Station and look forward to seeing the Cleveland Arcade. (Both buildings house their respective Hyatt Regencies.) However, I live in Chicago, and other Midwestern cities seem awfully quiet in comparison.

If the OP is truly weather-averse, Cincinnati has the Union Terminal museum complex: three museums in one space, about a mile from the Hyatt there. Dunno about whether that Hyatt is anything special.