This natural climate phenomenon, part of the ENSO (El Niño-Southern Oscillation) cycle, intensifies trade winds and brings deep, cold ocean water to the surface, changing temperatures and precipitation around the world. Although NOAA confirmed its presence in early 2025, this La Niña is weaker than previous ones and its duration may be short-lived.

La Niña is reaching the Pacific

After seven months of anticipation, La Niña—the cooler, opposite phase of El Niño—finally emerged in the eastern Pacific Ocean in early December 2024. However, the phenomenon may be short-lived. According to NOAA, the Pacific is expected to return to neutral conditions by spring 2025. La Niña is part of the El Niño-Southern Oscillation (ENSO) cycle and occurs when stronger-than-usual easterly trade winds push cooler, deep-sea water to the surface in the eastern tropical Pacific. This process causes large areas of the ocean near the equator to cool. The strengthened winds push warm surface waters westward toward Asia and Australia, causing changes in atmospheric moisture and influencing global weather patterns.

NOAA confirms La Niña conditions

In a report released on January 9, 2025, the NOAA Climate Prediction Center confirmed the presence of La Niña. Ocean surface temperatures were recorded as 0.7 degrees Celsius (1.3 degrees Fahrenheit) below average in the tropical Pacific, specifically in the Niño 3.4 region, which extends from 170° to 120° West longitude.

Signs of La Niña are also evident in the central and eastern Pacific Ocean in the form of areas of lower-than-average sea levels. This is caused by the retreat of cooler water, which lowers sea levels (while warmer water expands and raises them). This map, taken on January 13, 2025, shows sea level anomalies in the central and eastern Pacific Ocean—blue indicates lower sea levels, red indicates higher levels, and white indicates normal conditions.

Monitoring La Niña from space

Data for the map were acquired by Michael Freilich's Sentinel-6 satellite and processed by scientists at NASA's Jet Propulsion Laboratory (JPL). The analysis removed signals related to seasonal cycles and long-term trends to highlight sea level anomalies associated with ENSO and other short-term natural phenomena.

“Even though we have a La Niña here, it’s not a very strong one,” said Josh Willis, oceanographer and Sentinel-6 project scientist Michael Freilich of JPL. Willis added that during the exceptionally strong La Niña of 2010–2011, tropical Pacific temperatures in January 2011 were about 1.6°C (2.9°F) below average, while in January 2025 they were only 0.7°C (1.3°F) below average. NOAA predicts that this La Niña will likely fall short of the average 1°C mark and will be mild in strength. Neutral conditions are expected to return in the meteorological spring between March and May.

Global weather fluctuations ahead

The interaction between La Niña, the atmosphere, and the ocean changes global circulation patterns, which can lead to shifts in mid-latitude currents. This causes increased precipitation in some regions and drought in others. In the western Pacific, precipitation may increase over Indonesia and Australia. Cloud cover and precipitation in the central and eastern Pacific Ocean will become more sporadic, which can lead to drought in Brazil, Argentina, and other parts of South America, while Central America may experience higher humidity. In North America, cooler, stormier conditions often intensify in the Pacific Northwest, while the southern United States and northern Mexico tend to experience warmer, drier weather. ENSO adds natural variability to interannual global temperature changes. By cooling the Pacific, La Niña tends to lower average global surface temperatures. However, even the cold water in the Pacific does not completely offset long-term warming trends; some of the hottest years on record have coincided with La Niña, such as 2010 and 2020. Spring