The World Meteorological Organization's updated La Nina forecast on December 11 said there is a 55% chance of La Nina developing in the next 3 months.
However, the World Meteorological Organization notes that when it does appear, La Nina will be relatively weak and short-lived.
In a press release, the World Meteorological Organization emphasized that the latest forecasts from the WMO's Global Long-Range Forecast Center show that there is a 55% chance of a shift from neutral conditions (both El Nino and La Nina) to La Nina conditions between December 2024 and February 2025.
This figure is down from the 60% chance of La Nina occurring between December 2024 and February 2025 forecast by the World Meteorological Organization in September.
La Nina involves large-scale cooling of ocean surface temperatures in the equatorial central and eastern Pacific Ocean, along with changes in tropical atmospheric circulation, such as winds, pressure, and rainfall.
In general, La Nina produces large-scale climate impacts opposite to El Nino, especially in the tropics.
When it does appear, La Nina could end a spell of high temperatures that is expected to make 2024 the world's hottest year since records began.
“2024 started with an El Niño and is on track to be the hottest year on record,” warned Celeste Saulo, secretary-general of the World Meteorological Organization. “Even if La Niña does emerge, its short-term cooling effect will not be enough to offset the warming effect of record levels of heat-trapping greenhouse gases in the atmosphere.”
Since May 2024, there has been no El Nino or La Nina, a series of unusually extreme weather events, including record-breaking rains and floods, that "have unfortunately become the new norm in a changing climate," Celeste Saulo noted.
As of late November 2024, ocean and atmospheric observations continue to reflect ENSO-neutral conditions that have persisted since May. Sea surface temperatures are below average across much of the central to eastern equatorial Pacific.
However, this cooling process has not yet reached the typical La Nina threshold. The World Meteorological Organization pointed out that the delay in La Nina's appearance is due to the unusually strong westerly winds that are not favorable for La Nina's appearance that were recorded from September to early November 2024.
Seasonal forecasts of El Nino and La Nina and their associated impacts on global climate patterns are important tools for early warning and early response action.
