You have some very valid thoughts there but what large metropolitan areas are seeing is exactly the opposite with less cooling in the evenings. The reason? The heat islands thousands of square miles of asphalt and concrete are creating. I live in the Phoenix valley and looking at the temperature records our high temperatures really haven't risen much if any. However, our evening low temperatures are routinely breaking records for the highest low temperature for the date.

The other effect this is having is keeping the thunderstorms out of the valley during our monsoonal season. They build up on the outskirts of the valley, come rushing for us, hit the heat island and simply dissipate. Of course their humidity comes in which, along with the high temperatures, make the days pretty sweaty and of course, the dust storms and high winds make it in just enough to blow crap into my pool and turn it green routinely. So then, not only are you miserably hot, but you can't jump into the pool for refreshment.

However, there's hope on the horizon. Scientists tell us that global warming can reach that trigger point where the ice caps melt, disrupt the ocean convection currents and push us into a new ice age. Phoenix ought to become a lot like Flagstaff then, beautiful cool summers and some great skiing down the washes.