La Niña confirmed by NOAA in 2025

The United States National Oceanic and Atmospheric Administration (NOAA) confirmed this week the presence of the La Niña phenomenon in 2025. The event, which influences rainfall patterns and temperatures in several regions of the planet, is expected to remain active until February 2026, according to the agency.

According to NOAA, typical La Niña conditions established themselves by September 2025, evidenced by the expansion of areas with below-average sea surface temperatures (SST) in the central and eastern equatorial Pacific. The Niño-3.4 index—the main indicator of the phenomenon—recorded a weekly value of -0,5°C, while other regions ranged between -0,1°C and -0,4°C.

Although the event is still classified as weak, NOAA warns that it could influence global weather in the coming months. In the South Pacific and parts of South America, La Niña tends to favor greater rainfall.

In Brazil, the impacts are expected to vary by region:

• The North and Northeast may experience above-average rainfall and a greater risk of flooding;
• The Central-West and Southeast are expected to experience drier weather and milder temperatures;
• The South of the country tends to have reduced rainfall and a high risk of drought.