My personal observation is that longer flights seem to be smoother. Not sure if it's because you have more time in the air to get used to it, because the planes are different, because they fly higher/faster, because it's a longer router and they have more room to avoid rough air, something to do with flying with the jetstream instead of across it, or a combination of everything.
No one can really predict in advance what you will experience across such a long flight.
I'd say that November is probably one of the better months to fly across the southern half of the country. You don't get the violent heat-induced thunderstorms so frequent of summer. Florida is particularly thunderstorm prone in the summer, but by November it should be much smoother.