Prepare for unexpected vet bills
It may not offer much in the way of shade, but due to the elevation, seeing the Crazy Horse monument, which is a massive stone carving, can be a fun way to catch a cool upper-mountain breeze and see some interesting sights (and views) to boot.
It may not entirely cool you off, but it might still give you the chills! The Spokane Ghost Town is a former mining town that was left abandoned decades ago and can still be explored by the brave and careful (much of it is crumbling). If that's not enough, you can also check out the Okaton Ghost Town too!