I'm not sure but think that American persimmon are like Asians. They have a low chilling requirement and break dormancy based on heat units. Pecans, figs, and grapes fall in the same category. Low chilling requirement but high heat requirements to leaf out. Thus they leaf out late but are very freeze sensitive, both foliage and flowers, after leafing out.

Based on that in zone 7 they will get enough dormancy by the first of the year. Pull them inside after that and pile on the heat units to break them out of dormancy.

Are you saying that by the end if the calendar year in zone 7, they should have enough chill hours and I can bring them in?

ForestandFarm:

That's what I'd do. When I lived in Amarillo 400 miles north of here, zone 6-7, I felt all crops had enough chilling by sometime in January. Chilling during the early part of dormancy is the most effective. Those persimmon will be ready to go by Jan 1.

All zone 7 climates aren't the same. Out east zone 7 gets more chilling than Amarillo. The more clouds the better as long as it's not constantly below freezing. 40-45F is the most effective. Four weeks at constant 40F and they'd be ready, probably even two weeks at 40F after they drop their leaves.