November 2025 ENSO Outlook: Short-lived La Nina Followed by El Nino Middle Third 2026

November 2025 Climate Impact Company ENSO Outlook

Issued: Thursday November 13, 2025

Highlight: Short-lived La Nina followed by El Nino during middle third of 2026.

Executive summary: The monthly Climate Impact Company ENSO Outlook indicates the current weak La Nina should strengthen slightly and peak by January followed by rapid dissipation and a possible reversal in ENSO phase to El Nino during the middle third of 2026. The La Nina climate appears locked-in for late 2025. However, an active Madden Julian oscillation (MJO) should break the La Nina during mid-to-late Q1/2026. The active MJO promotes warming waters of the subsurface equatorial Pacific Ocean increasing risk of El Nino by middle 2026. Marine heatwaves are dominant and (regionally) continue to influence climate mostly by raising the risk of anomalous warmth and high impact heavy precipitation events.

Discussion: The global SSTA pattern as of early November (Fig. 1) begins includes presence of a weak La Nina and a stronger negative Indian Ocean dipole (-IOD). The tropical SSTA pattern is a contributor to the recent global vertical velocity regime whereas negative values represent convection across warmer than normal tropical waters countered by subsidence in the longitudes of the Americas where subsidence has dominated (Fig. 2). Usually, convection zones are wetter than normal and subsidence zones are drier than normal although local topography can influence the relationship. Marine heat waves (MHW) are dominant in the middle/subtropical latitudes of both hemispheres and leading ongoing contributors to increasing global SSTA (Fig. 3). The global SSTA forecast by the International Multi-modal ensemble (IMME) indicates La Nina peaks in January while IOD shifts to neutral phase (Fig. 4). The IMME model likely over forecasts the strength of MHW’s in the northern hemisphere. Note evolution of the Amundsen Sea warm hole (ASWH) in the southern hemisphere due to fresh water gathering of rapid Antarctic ice. By April, IMME dissipates La Nina and indicated some warming in the Nino12 region off the northwest coast of South America (Fig. 5). The warming is a sign of EL Nino potential which is indicated for JUN/JUL/AUG 2026 by the Climate Impact Company constructed analog forecast (Fig. 6). Elsewhere, during April, MHW’s are biased farther south in the southern hemisphere and vividly present across northern hemisphere oceans including northern latitudes.

Fig. 1: November 2-8, 2025, global SSTA observations and annotations of key SSTA regions.

Fig. 2: The vertical velocity anomalies identifying convection and subsidence areas for October 2025.

Fig. 3: Monthly SSTA from 1982-2025.

Fig. 4: The IMME global SSTA forecast for January 2026.

Fig. 5: The IMME global SSTA forecast for April 2026.

Fig. 6: The Climate Impact Company constructed analog Nino34 SSTA forecast reveals a short-lived La Nina followed by a potential El Nino by later Q2/2026.