When we lived in Las Cruces, NM over 40 years ago, we went to Phoenix - once - thought I would die. Showing the NJ nephew around, so not much choice on dates.
Was it 100 degress by 10am? And I thought NM was hot in the summer!
Flagstaff is also the sort of entry and miles from the Grand Canyon from the south, IIRC, if that interests you.
Do I remember pine trees in Flagstaff?
My wife and I have stayed in Flagstaff three times in the last ten years. What people should know about Flagstaff is that it’s about 7000 feet in elevation and, while warmer than Wisconsin where we live, can get pretty cold in the winter.
In a couple months it'll be well over 100 by 10PM.