Potential La Nina Return May Impact Global Weather Patterns: WMO Report

New Delhi, Sep 2 (PTI) - The World Meteorological Organization (WMO) has announced the potential return of La Nina, which could affect global weather and climate patterns starting from September. Despite La Nina's temporary cooling influence, global temperatures are predicted to remain above average across much of the world.

La Nina and El Nino are the two opposing phases of a climate cycle related to the Pacific Ocean. El Nino is characterized by the warming of ocean waters near Peru, which often leads to the weakening of India's monsoon and warmer winters. Conversely, La Nina involves the cooling of these waters, typically resulting in a stronger monsoon for India and colder, harsher winters.

The WMO highlights that these naturally occurring climate events are unfolding against the backdrop of human-induced climate change, which is elevating global temperatures, intensifying extreme weather, and altering rainfall and temperature patterns.

Since March 2025, neutral conditions—neither El Nino nor La Nina—have persisted with sea surface temperature anomalies near average across the equatorial Pacific. However, these conditions might shift toward La Nina from September, according to the WMO.

Forecasts from WMO's Global Producing Centres for Seasonal Prediction suggest a 55 percent chance of sea surface temperatures in the equatorial Pacific cooling to La Nina levels and a 45 percent chance of remaining ENSO-neutral from September to November 2025.

For the period from October to December 2025, the probability of La Nina increases to about 60 percent, while the likelihood of El Nino remains low.

"Seasonal forecasts for El Nino and La Nina and their associated impacts on our weather are crucial climate intelligence tools. They translate into economic savings for sectors like agriculture, energy, health, and transport and have saved thousands of lives when used to guide preparedness and response actions," said WMO Secretary-General Celeste Saulo.

While the El Nino-Southern Oscillation (ENSO) significantly drives global climate patterns, it is not the sole factor influencing the Earth's climate. WMO's Global Seasonal Climate Updates also consider other variability patterns such as the North Atlantic Oscillation, Arctic Oscillation, and Indian Ocean Dipole.

For the September to November period, the latest update projects above-normal temperatures in much of the Northern Hemisphere and large areas of the Southern Hemisphere, with rainfall patterns resembling those typically observed during a moderate La Nina.