La Niña may develop, but it is likely to be weak and short-lived
La Niña conditions may develop in the next three months but are expected to be relatively weak and short-lived, according to the latest Update from the World Meteorological Organization.
- La Niña tends to have a short-lived cooling effect
- It does not reverse long-term human-induced global warming
- 2024 remains on track to be hottest year on record
- “Neutral” (neither El Niño nor La Niña) conditions currently prevail
- Seasonal forecasts inform climate-sensitive sectors
Latest forecasts from WMO Global Producing Centres of Long-Range Forecasts indicate a 55% likelihood of a transition from the current neutral conditions (neither El Niño nor La Niña) to La Nina conditions during December 2024 to February 2025.
The return of the ENSO-neutral conditions is then favored during February-April 2025, with about 55% chance.
La Niña refers to the large-scale cooling of the ocean surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation, such as winds, pressure and rainfall. Generally, La Niña produces the opposite large-scale climate impacts to El Niño, especially in tropical regions.
However, naturally occurring climate events such as La Nina and El Nino events are taking place in the broader context of human-induced climate change, which is increasing global temperatures, exacerbating extreme weather and climate, and impacting seasonal rainfall and temperature patterns.
“The year 2024 started out with El Niño and is on track to be the hottest on record. Even if a La Niña event does emerge, its short-term cooling impact will be insufficient to counterbalance the warming effect of record heat-trapping greenhouse gases in the atmosphere," said WMO Secretary-General Celeste Saulo.
“Even in the absence of El Niño or La Niña conditions since May, we have witnessed an extraordinary series of extreme weather events, including record-breaking rainfall and flooding which have unfortunately become the new norm in our changing climate,” said Celeste Saulo.
As of the end of November 2024, oceanic and atmospheric observations continue to reflect ENSO-neutral conditions which have persisted since May. Sea surface temperatures are slightly below average over much of the central to eastern equatorial Pacific.
However, this cooling has not yet reached typical La Niña thresholds. One possible reason for this slow development is the strong westerly wind anomalies observed for much September to early November 2024, which are not conducive for La Niña development. The previous Update, issued in September, forecast a 60% likelihood of la Niña in December-February.
Seasonal forecasts for El Niño and La Niña and the associated impacts on the climate patterns globally are an important tool to inform early warnings and early action.
Global Seasonal Climate Update
Given that the El Niño Southern Oscillation (ENSO) is not the only driver of the Earth’s climate system, WMO also issues regular Global Seasonal Climate Updates (GSCU). These updates incorporate the influences of other major climate variability modes, including the North Atlantic Oscillation, the Arctic Oscillation and the Indian Ocean Dipole. The updates also monitor the status of North Tropical Atlantic (NTA) and South Tropical Atlantic (STA) Sea Surface Temperature index anomalies.
The latest GSCU indicates that widespread above-normal sea-surface temperatures are expected to persist in all ocean basins apart from the near-equatorial eastern Pacific Ocean (consistent with the predicted likely emergence of weak La Niña conditions). As a result, above-normal temperatures are predicted over almost all land areas.
Predictions for rainfall for December 2024 to February 2025 are consistent with the enhanced positive east to west sea surface temperature gradient typically observed during La Niña.
The WMO Updates are based on WMO Global Producing Centres of Long-Range Forecasts and are designed to support governments, the United Nations, decision-makers and stakeholders in climate-sensitive sectors to protect lives and livelihoods.
WMO Regional Climate Centres and National Meteorological and Hydrological Services (NMHSs) will closely monitor changes in the state of ENSO over the coming months.
The World Meteorological Organization (WMO) is a specialized agency of the United Nations responsible for promoting international cooperation in atmospheric science and meteorology.
WMO monitors weather, climate, and water resources and provides support to its Members in forecasting and disaster mitigation. The organization is committed to advancing scientific knowledge and improving public safety and well-being through its work.
For further information, please contact:
- Clare Nullis WMO media officer cnullis@wmo.int +41 79 709 13 97
- WMO Strategic Communication Office Media Contact media@wmo.int