If you find him trying to escape heat, or constantly hiding on the coolest end of the tank, that could indicate he is overheating- which is why the temp gun is important. You mention temps of 100 degrees for 2 months. Make sure his tank never reaches those heights, and if this becomes a risk of occurring, move his tank to a cooler, more appropriate area of your house (which you can even determine with the temp gun) and away from windows, or direct sunlight. Dehydration, heat stroke and even death become a risk in those conditions. They need to be able to move about their tank to regulate their body temps- be it 92-95 degrees, or 73-75.