I do this a lot through the summer. The nighttime temperatures are often below 75F. I think the secret might be in the placement of the open windows. If you can get a good flow going east/west and north/south, you might be able to exchange air quickly...

However, for my house, when temps go above 78F in the night, this doesn't seem to work as well.

On those nights, I am tempted to set up a tent and sleep in the backyard (a balcony might be even cooler if you live in a second story apartment.). Fortunately last summer was very mild here and even when it isn't mild, the higher temperatures last only a week or so.