For the not so hot days and cool nights you could open the windows at night and first thing in the morning close the windows and pull the shades. That will cool the house at night then trap the cool air in the house through the day the interior will get warmer but with good insulation the temp should only get up to the difference in morning temp to day time high. House gets down to 60F high of 90F temp should get to around 75F. This might not work so well depending on how exposed the house is and if there is not much insulation.
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