The weather should be gorgeous then, you can expect highs in the 70's with sunny skies, however i'd bring some warm clothes just in case... nice weather certainly isn't guaranteed
There's a lot of great riding down here, granted for road riding i've only really explored the NE area of the valley myself. Not sure what kind of riding/level/distance you do now but check out strava.com for some ideas of where people are riding down here in the valley. I'd definitely recommend checking out the carefree/cave creek area.