WMO Forecasts 55% Chance of Weak La Niña Event from December 2025

The World Meteorological Organization (WMO) has announced a 55% probability of a weak La Niña event occurring from December 2025 through February 2026, a development that could influence global weather patterns and have significant economic implications across various sectors.

La Niña is characterized by cooler-than-average sea surface temperatures in the central and eastern equatorial Pacific Ocean. Despite its typical cooling effect on global temperatures, many regions are still expected to experience above-average temperatures, increasing the risk of extreme weather events such as floods and droughts. These conditions can significantly impact agriculture, water resources, energy demand, health, and transportation.

According to the WMO, there is also a 65% to 75% chance of neutral climate patterns developing between January and April 2026. The organization emphasized the importance of accurate seasonal forecasts for sectors like agriculture, energy, health, and transport, as they can lead to substantial economic benefits and help save lives by enabling better preparation.

La Niña events typically occur every two to seven years and can last from several months to two years. They are part of the El Niño-Southern Oscillation (ENSO) cycle, which also includes El Niño events characterized by warmer-than-average sea surface temperatures in the same region.

The previous La Niña event began in December 2024 and was short-lived, ending by March 2025. This event was weaker and shorter than typical La Niña occurrences, with limited influence on global weather patterns.

WMO Secretary-General Celeste Saulo emphasized the importance of seasonal forecasts, stating that they are "an important tool to inform early warnings and early action" and can lead to "millions of dollars’ worth in economic savings for key sectors like agriculture, energy, and transport" while saving lives by enabling disaster risk preparedness.

The potential development of a weak La Niña event has several economic and societal implications:

• Agriculture: Changes in precipitation and temperature patterns can affect crop yields, impacting food supply and prices.

• Energy: Altered weather patterns can influence energy demand, particularly for heating and cooling.

• Health: Extreme weather events associated with La Niña, such as floods and droughts, can have direct and indirect health impacts, including injuries, waterborne diseases, and mental health issues.

• Transport: Severe weather conditions can disrupt transportation networks, affecting the movement of goods and people.

The WMO's forecast of a 55% chance of a weak La Niña event from December 2025 through February 2026 underscores the need for vigilance and preparedness across various sectors. While La Niña typically brings cooler global temperatures, the ongoing trend of global warming may offset this effect, leading to complex and region-specific impacts. Accurate seasonal forecasts and proactive measures are essential to mitigate potential adverse effects on agriculture, water resources, health, and the economy.