I've been getting anxious to aerate and overseed out here too, so I looked up your cooperative extension guidelines on this. They pretty clearly don't want you to aerate in August. I'm guessing they aren't taking into account crazy weather years, but at the same time, you are likely to still get some hot dry weather again before the end of the summer, right?:

http://www.turffiles.ncsu.edu/PDFFiles/00001...

Mid-Sept is good. Wait until a day after a good rain so the tines can sink deeply in the soil