Our house has central air but the upstairs (finished attic) gets warm because heat rises. The kids like to be upstairs even when its' hot and stuffy (cant figure that one out) during the day. When it's really hot in the 90's I'm always checking on them throughout the day.
Most of time they are downstairs with us during the day, where it is cool.
At night it cools off upstairs so they go between up/down stairs.