The summer has been the top season for births in the United States, according to records kept by the Centers for Disease Control and Prevention, and August often wins the title as the month during which the most babies are born.
Seasons and weather conditions play a role in birthdays, according to Paul Sutton, another CDC health statistics demographer. He theorizes that as the mercury drops in the late fall and winter, things heat up at home as people spend more time indoors. About nine months later, a summer baby is born.