Get a pillar fan from your local Walmart. They can really put out the air. Someone else suggested a shop fan, which is compact, noisy as all getout, but if you're at work during the heat of the day, no sweat.
Personally, I'm paranoid. If the lethal temperature is 85, and my thermometer, which cost less than 10.00, says 84---what if it's wrong by one degree? Give yourself as much room as you can.
At worst, you can reverse your day night cycle to put the lights on during the cool of the night. The fish don't care.
There's a thread in the Discussion forum called "other factors in bleaching" that is worth reading, re heat and its effects.