I think it all has to do how your house is situated ie. the direction the house faces, if your bedroom is on the northwest side for instance you will not need to turn on the AC on until late in the morning if your sleeping in etc.. on most summer days etc..
If you have a newer home it is likely very well insulated, and if you have Dual zone AC (upstairs/Downstairs) and you spend most of your time during the day downstairs your AC bill will be much less if you only use the downstairs unit.
We have a new home with Dual zone in T.V. with all tile flooring downstairs and it is a rare day we have the AC on before 1: PM in the afternoon in the summer.
At night it cools down very fast on most days and we just put a box fan in the window in the upstairs bedroom and it does a wonderful job.
Our electric bill is usually far less than $100 even during the summer time.
Also having a pool can cost you a lot more in electricity than the AC unit.
And if it is just a real stinker of a hot day we just jump in the car, turn on the AC and head to la jolla to go snorkeling
