NOAA confirms rare weak La Niña, expected to last through spring 2025
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The National Oceanic and Atmospheric Administration (NOAA) has confirmed the onset of a rare and weaker-than-usual La Niña event, which is anticipated to influence global weather patterns until spring 2025.
This cooler phase of the El Niño-Southern Oscillation (ENSO) cycle, which affects atmospheric and oceanic conditions in the tropical Pacific, is unusual for its delayed arrival and shorter duration.
Initially predicted to develop in 2024, the La Niña event only emerged in December, following record-high ocean temperatures earlier in the year. NOAA’s data indicates a 59% chance that La Niña conditions will persist through February to April, with a 60% probability of transitioning to neutral conditions by spring.
The phenomenon is characterised by sea surface temperatures dropping below the La Niña threshold of 0.5 degrees Celsius. Its effects on global weather are typically felt through wetter winters in northern regions and drier conditions in the southern United States.
La Niña and El Niño events typically alternate every two to seven years, lasting about a year each. However, the current La Niña has defied initial predictions with its weaker intensity and delayed development. Scientists are still investigating the factors behind this anomaly, particularly the influence of elevated ocean temperatures recorded in 2024.
For this event to be officially included in NOAA’s historical record, La Niña conditions must continue across five consecutive three-month seasonal periods. NOAA scientists are closely monitoring the tropical Pacific to understand the potential duration and impacts of this La Niña on global weather patterns.