According to the United Nations University: “It is an important climate phenomenon that can shape weather patterns across the globe, bringing floods, droughts, heatwaves and storms to different regions. Occurring every two to seven years, El Niño events can be forecast several months in advance, although their timing and intensity remain difficult to predict and their impacts can be severe.”
Article source: https://www.huffingtonpost.co.uk/entry/winter-el-nino-weather-warning-met-office_uk_6a9aeca2e4b0bd4d29d4183a