what would be the optimal temperature (climate) for battery performance?
Coastal California - seldom into the 40's, seldom into the 90's.
The truth is that the Battery Management System will heat the battery if the temps are too cold, and cool the battery if the temps are too high, so the battery really doesn't care about the climate. This heating/cooling will reduce your range on a charge, with heating taking more power than cooling, so living in Santa Barbara will probably give you the maximum lifetime efficiency.
In the high 70’s/low 80’s. Anything outside of that, the BMS will do what it has to, to keep the battery happy.