If you’ll be downtown, business dress is appropriate for the day, and going casual is the approach at night. Museums rarely require jackets, and you see a lot of jeans and gym shoes. Be aware that this is a city with four seasons, and the winter can be brutal, so come dressed for the cold and inclement weather if you’ll be here in colder months. It is up to individual businesses to shovel their sidewalks, so snow boots are not a bad idea if you foresee walking. The attitude in Cincinnati is pretty no nonsense about staying warm—hats are basic and effective, nothing too frilly.
If your visit means you’ll be in the Hyde Park area, think more fashion forward. It’s a charming area with chic shops. Remember too that Tiffany and Saks Fifth Avenue are here, so if you’re really in a jam or need a gift, you can find familiar territory.