El Niño/La Niña Update


The El Niño/Southern Oscillation has a major influence on climate patterns in various parts of the world. This naturally occurring phenomenon involves fluctuating ocean temperatures in the central and eastern equatorial Pacific, coupled with changes in the atmosphere. Scientific progress on the understanding and modelling of this phenomenon has improved prediction skills to within a range of one to nine months in advance, giving society the opportunity to prepare for associated hazards such as heavy rains, floods and drought.


The El Niño-Southern Oscillation (ENSO) status in the tropical Pacific remains neutral, signifying that neither El Niño nor La Niña is currently occurring. However, since May both surface and sub-surface waters in the region have leaned to below average. The latest forecasts from the WMO Global Producing Centers of Long Range Forecasts indicate that tropical Pacific sea surface temperatures are likely to cool further, potentially reaching La Niña levels during September 2020. Given current conditions and model predictions, the chance of La Niña during September-November 2020 is estimated to be around 60%, with about a 40% chance for ENSO-neutral conditions to continue. Chances for La Niña decrease to 55% for the December-February 2020/2021 period. National Meteorological and Hydrological Services will closely monitor changes in the state of ENSO over the coming months and provide updated outlooks.

In summary:

• The tropical Pacific has been an ENSO-neutral condition since July 2019. However, since May 2020, sea surface temperatures over the area have leaned slightly towards below-average.

• Current observations show below-average surface and sub-surface water temperatures in the tropical Pacific, suggesting a likely tendency towards further decreases in sea surface temperature, possibly reaching La Niña thresholds during September 2020.

• Model predictions and expert assessment indicate that the probability for La Niña development during September-November 2020 is about 60%, while that for ENSO-neutral conditions continuing is 40% and that for El Niño is near-zero. For the December-February 2020/2021 season, the probability for La Niña slightly drops to about 55%, while that for ENSO-neutral remains at 40% and that for El Niño marginally rises to 5%.

• Sea surface temperatures in the east-central Pacific Ocean are most likely to be in the range of 0.3 to 1.3 degrees Celsius below average during September-November 2020, and 0.1 to 1.2 degrees below average during December-February 2020/2021.