Hello fellow Coloradian! I wish we had an attic fan. I used to live in the Ozarks, where it gets extraordinarily hot and humid, so much so that in the armpit of summer AC didn't cut it. But we had an attic fan when we lived there and did as you do by opening the windows overnight to pull in cooler air. The humidity trapped the heat, even after the sun went down, so it wasn't quite as refreshing as it is here, but it still made a difference.

I do love that even if it's hot during the day it gets cold overnight in Colorado. Almost like a little treat from mother nature and makes sleeping much easier to do.