Plants is very sensitive to temperature, no matter indoor grow or outdoor grow, when the temps are so high, low humidity or light too close the plants, the plants will have heat stress problem.
Sign of Heat Stress
Plants leaves will become yellow or brown spot, When the heats gets too high, the edges of the serrated leaves will begin to curl up and the leaves will begin to “cup”
Buying a temperature monitor to monitor the temps, according the monitor to adjust the temps to help plants keep in comfortable environment. For the indoor grow, good ventilation system is very important, keep the light don’t close to your plants.