I'm in northeast Florida and my outdoor system is doing fine. the res temp has been sitting at 85-90 degrees and there havent been any ill effects. I do swap out frozen 2 ltr bottles of water in the res once a day.
tomato roots 2 weeks
tomato roots 3 weeks
I'm planning to move and expand the system since I'm starting a commercial produce business. I'll bury the res when i move the system which should help keep the temps down.