Mountain Biking in Arizona is wonderful. Great places in the Valley of the Sun in the Winter. Great in the high country in the Summer.
You can always ride in the Phoenix Metro area, but in July and August you’ll need to start early and finish early.
South Mountain (ranked top 10 in the country by Mountain Biking Mag)
Prescott ( pronounced Press Kit)
Highline Trail (Strawberry/Payson/Christopher Creek/Horton Spring)