I can't seem to get my grow room temps below 83f i have a portable air cond about 15 feet away exhausting out a patio door. I have a fan blowing into room and 1 blowing out. 400 watt hps. I'm on 12/12, dark period temps are 77f. Am I in great danger of heat stress? They look like they are doing well 2weeks in flower @ 36" tall, 4 plants in all.
So I have always heard the plant will start to stress at 80. I grow WW and I keep it under that, but my first crop due to some major stupidity got hot regularly, and they still did OK. Get it under 80 if you can. But I think you will be ok. There are outdoor growers and people all around here that regularly grow in hotter temps.