https://www.kxnet.com/news/national-news/will-el-nino-make-airplane-turbulence-worse/ ". . . link between El Niño or La Niña years and the amount of clear-air turbulence (or CAT) in the atmosphere." ". . . during El Niño years, there were more wind shear anomalies over the United States, Mexico, Southeast Asia and Australia. In La Niña years, the opposite was true — there was weaker wind shear."