SBTCO,
A lot depends on the duration of the warm temperatures. The best solution is not to allow them to get much above 70, if possible.
In my part of Montana it almost always cools off to no more than 70 at night, even in the hottest part of the summer. My garage gets considerably warmer, of course, even with the shade trees we planted on the southwest side. But the daytime temperature inside the coolers never rises above 75, and most days never reaches 70.
