My dad used to say that before daylight savings time. Since central Indiana has adopted daylight savings time, now our air conditioners have the greatest demand later in the day. For many people, the air conditioner works its hardest right after we get home from work when we want to be comfortable. Often times this is also when we are cooking, doing laundry or going in and out the door. Sometimes the demand is as much as 40% greater at that time than the average for the rest of the day. To make the problem worse, most existing air conditioners are either working or not. They are unable to adjust to the changing demands of our homes throughout the day. Some new comfort systems have two stages or more to adjust to the demands of your home. Combined with variable air flow, these systems are like two air conditioners in one. One very efficient and small air conditioner for the majority of the time, and another large air conditioner for those evenings when the heat, humidity and people in our homes can make it very uncomfortable.
See this chart about how the sun affects your air conditioner