re: Northern Arizona (Sedona, Grand Canyon...etc) Summer Question

Not sure how much my experience will help, but I'll throw out the data point. Did the Utah parks, Zion and Bryce Canyon around the summer solstice a few years ago. Gets you about 16 hours of sunlight going at that time, which was awesome but also quite warm. Drove down to the North Rim of the Grand Canyon one day and the thermometer on the vehicle ranged from 100 degrees in Utah to about 40 approaching the Grand Canyon. Fantastic trip. Even with the heat of Utah, the dry air allowed for the temps to be very comfortable, even crisp in the early morning hour.