In most cities, the hot and humid weather experienced during August carried through September, wrapping up an expensive cooling season. Check out the wet bulb design hours for Miami: there were 270 hours when the wet bulb temperature was equal to or above the ASHRAE 0.4% design condition of 80 degrees F (normally 35 hours for an entire year). This may be an extreme case, but it's a sobering reminder of the potentially large swings in wet bulb design hours from year to year. This can cause serious migraines when dealing with cooling towers that are overloaded.
Right now, you may be thinking, "How do I measure the impact of high humidity levels on my utility bills?" One popular method is to graph monthly energy costs against cooling degree days (CDD's). It is often assumed that if the CDD's were near or lower than normal for a given month, then the weather can be ruled out as a possible reason for a simultaneous increase in energy costs. Not a very good assumption, especially where large ventilation loads are present because CDD's ignore latent cooling (dehumidification) loads. CDD's are calculated by simply subtracting a space neutral temperature (usually 65 degrees) from the average daily dry bulb temperature.