La Niña conditions have developed in the tropical Pacific, with both oceanic and atmospheric indicators reaching the necessary thresholds during the September-October 2021 period. The latest forecasts from the WMO Global Producing Centres of Long-Range Forecasts indicate a high chance (90%) of tropical Pacific sea surface temperatures remaining at La Niña levels until the end of 2021, and a moderate chance (70-80%) for them to persist at La Niña levels through the first quarter of 2022.