WASHINGTON—The ozone hole near the South Pole this year is the smallest since it was discovered, but it is more due to freakish Antarctic weather than efforts to cut down on pollution, National Aeronautics and Space Administration (Nasa) reported. This fall, the average hole in Earth’s protective ozone layer is 3.6 million square miles (9.3 million square kilometers). That’s down from a peak of 10.3 million square miles (26.6 million square kilometers) in 2006. This year’s hole is even smaller than the one first discovered in 1985. “That’s really good news,” Nasa scientist Paul Newman said Tuesday. “That means more...