In Japan, historical data has shown that El Niño years tend to lead to warmer winters. However, there have also been cases of cold winters in Japan during El Niño years, such as the one recorded in 2014-2015. “Each El Niño is individually unique, and no two El Niños are exactly alike,” explains Post-doctoral Fellow Masahiro Shiozaki who authored the study. This was an El Niño year, and in Japan that tends to mean a warmer winter. In this simulation, 1700 El Niño events occurred, and we calculated how the atmosphere changed each time.