Phoenix is a very dry heat, very little humidity. 120F is toasty, but its nothing a pool and margarita can't solve :). Our winters are fantastic. We have 300+ days of sun shine! We are 2-3 hours to the Mexican beaches, 2 hours to snow for snowboard/ski (flagstaff), lots of golf, lots of hiking, lots of Tech work (Motorola was a monster back in its day, Intel has a huge presence, Godaddy, Paypal, the list goes on), Baseball Spring Training is awesome!
Oh right it's dry, confused it with Houston :) But still, an average high above 100F for 4 months is pretty brutal. I'm guessing people don't spend much time outside during the summer months (during the day at least), unless it involves some water activity.
A lot of people don't spend time outside in most places :|
I personally like the heat (over the cold). I mountain bike with my kids at dawn in summer. We camp in Flagstaff which is 30-40 deg cooler (7500ft elevation) and only 2 hours away.