Research, more research and a small dose of commonsense can save you a bit of pain.
"It's also really hot in August, not just 'Wow it's hot out here!' but more like, 'Did you see that squirrel spontaneously-combust?' hot."
After doing a few minutes of research about what kind of weather conditions to expect in the South West around early August I discovered that the region does have a rain/monsoon season, though it may not always be wet it will be windy. The season(s) throughout the area runs from June to August; since we're covering a lot of road on this trip (2,000 miles plus one way) we have to deal with several regions' unique annual conditions. More over, it's also really hot in August, not "Wow it's hot out here!" but more like, "Did you see that squirrel spontaneously-combust?" hot. "Oh but its a dry heat", kiss my ass, 100°+ is hot.
Seeing as this trip is as much about my photography as it is my love of the road and travel, the idea of battling these conditions at their worst isn't ideal. As such, we've decided to move the trip back to September, we still need to hammer out a solid date, route, points of interest, accommodations, what car to take, ect... It's early, we'll get it set-up before we have to pack and you all get to come allow for the ride.
Knowing my past with getting things ready for a project we'll probably have everything ironed out by the time we hit Arizona.