what is williamsburg's weather REALLY like in the fall?

hi, all. i've read some conflicting things about williamsburg in the fall. i realize that the highs in september and october can routinely reach the high 70s and 80s. but i also know that "highs" don't tell you everything. for example, i've lived in places where it might be 50/60 degrees for most of the day, then peak at 80 for an hour before falling in temps again.

anyway, my partner and i are mostly looking at places in the northeast to move to but williamsburg is one of the few southern places still on our list. the one thing we're not sure about is the fall weather. (we usually travel in the summer, so that's not as much of an issue). we really love the fall though and by september, we're sick to death of heat, so if williamsburg feels more like summer well into october, we'd have to rethink it.

so for those that live there or visit in the fall frequently, what is it really like? is september pretty unbearably hot? october too? when does it start to really cool down and feel like fall?

thanks for any advice