La Niña conditions persist in early 2025, though meteorologists predict a transition to ENSO-neutral conditions by March–May, with a 66% probability. This year’s La Niña has been weak and short-lived, presenting an interesting dynamic between oceanic and atmospheric factors. While the Pacific Ocean’s surface temperatures indicate only a mild La Niña, the atmospheric response has been stronger than expected. This update explores current conditions, the forecast, and the impact of this unusual ocean-atmosphere interaction.
La Niña is part of the El Niño-Southern Oscillation (ENSO) cycle, which influences global climate patterns. When La Niña is active, cooler-than-average sea surface temperatures in the central and eastern Pacific Ocean alter atmospheric circulation, affecting weather across the globe. Conversely, El Niño brings warmer-than-average waters, shifting climate patterns in the opposite direction. ENSO-neutral conditions occur when ocean temperatures are near average.
Because ENSO can be predicted months in advance, it serves as an important tool for anticipating extreme weather events, including hurricanes, tornadoes, droughts, and flooding. It also has economic implications, influencing agricultural yields, financial markets, and energy consumption patterns.
The primary indicator of La Niña is the Niño-3.4 sea surface temperature index, which tracks temperature anomalies in the east-central Pacific Ocean. In January 2025, the Niño-3.4 index registered at -0.8°C, marking the second consecutive month within the “weak” La Niña category (-0.5°C to -0.9°C). While sea surface temperatures indicate only a mild La Niña, the atmosphere tells a different story.
The atmospheric component of La Niña is characterized by stronger-than-average trade winds, increased rainfall over Indonesia, and drier conditions in the central Pacific. These patterns were evident in January, demonstrating a robust atmospheric response despite weak oceanic anomalies. This discrepancy suggests that La Niña’s influence on global weather may be more pronounced than ocean temperatures alone indicate.
Climate models suggest that La Niña will persist for a few more months before transitioning to ENSO-neutral conditions. There is a 41% chance of neutral conditions emerging between February and April, but the most likely transition period is March–May.
Looking further ahead, ENSO-neutral conditions are favored for the latter half of 2025, though there is a slight tilt toward another La Niña event next fall. While it is too early to predict with confidence, historical data suggests that back-to-back La Niña years are not uncommon.
One interesting observation from January 2025 is that subsurface ocean temperatures in the tropical Pacific were the third coolest on record since 1979. Historically, similar conditions have preceded a return of La Niña later in the year, but the sample size is too small to draw firm conclusions.
Meanwhile, global ocean temperatures have been significantly above average, which may be influencing La Niña’s behavior. Scientists are exploring a “relative Niño-3.4 index,” which adjusts for overall ocean warming to better isolate ENSO-related changes. Early findings suggest that traditional ENSO measurements may need refinement to account for global climate shifts.
While the current La Niña remains weak, its atmospheric impact is stronger than expected, influencing weather patterns worldwide. The transition to ENSO-neutral conditions is likely by mid-2025, but long-term forecasts hint at the possibility of another La Niña event later in the year. With global ocean temperatures rising, scientists are reevaluating how La Niña and El Niño are measured, which could lead to improved forecasting models in the future.
