The electricity consumed in a given period (often referred to as electricity load) varies throughout the year in somewhat predictable patterns. Total U.S. hourly electricity load is generally highest in the summer months when demand peaks in the afternoon as households and businesses are using air conditioning on hot days. During the winter months, hourly electricity load is less variable but peaks in both the morning and the evening. Load is generally lowest in the spring and autumn when homes and businesses have less need for space heating or cooling.