New sensor technologies that monitor sleep objectively indicate that the average adult in the United States, Germany, Italy, and Australia tends to sleep about six and a half hours in the summer when it is warm and light and between seven and seven and a half hours in the colder, darker winter months.24 Altogether and despite much variation, most adult Westerners probably average about seven hours a night, a good hour (13 percent) less than the eight hours we supposedly need.
