I live in central Florida, where it's a race in the morning between the temperature and humidity to see which can get to 90 first. In terms of cooling the car down initially, the Prius is the best vehicle I've owned, although my '91 F150 with a short cab and new a/c system is awfully good. Maintenance of a comfortable cabin is a little dicey, since your orientation wrt the sun makes a big difference, and the a/c sensors don't take insolation/radiant effect on the body into account. I'm always fiddling with the [steering-wheel mounted] temperature adjustment. All in all, it's very good. Also, on a cold day it heats up the cabin MUCH faster than conventional systems based on the engine coolant temperature.