During the last month, ENSO-neutral conditions emerged, as indicated by near-average sea surface temperatures (SSTs) in the central and east-central equatorial Pacific Ocean [Fig. 1]. The latest weekly Niño-3.4 index value was -0.2°C, with the westernmost (Niño-4) and easternmost (Niño-1+2) indices at +0.3°C and +0.6°C, respectively [Fig. 2]. The equatorial subsurface temperature index (average from 180°-100°W) increased for the fifth consecutive month [Fig. 3], with above-average subsurface temperatures extending across the Pacific [Fig. 4]. Westerly wind anomalies were observed over the western equatorial Pacific at low levels, and were evident over the eastern Pacific at high levels. Convection was near average over the Date Line, with suppressed convection over western Indonesia [Fig. 5]. Collectively, the coupled ocean-atmosphere system reflected ENSO-neutral conditions.

The North American Multi-Model Ensemble (NMME) average, including the NCEP CFSv2 [Fig. 6], favors ENSO-neutral through April-June 2026, with a transition to El Niño thereafter. El Niño is likely because of increasing subsurface temperature anomalies and recent westerly wind anomalies over the western Pacific Ocean. However, the possible outcomes range from ENSO-neutral to a very strong El Niño during the upcoming Northern Hemisphere winter [Figs. 7 & 8]. The possibility of a very strong El Niño (1 in 4 chance of Niño-3.4 ≥ +2.0°C) largely depends on the continuation of westerly wind anomalies across the equatorial Pacific throughout the Northern Hemisphere summer months, which is not assured. In summary, ENSO-neutral conditions are present and are favored through April-June 2026 (80% chance). In May-July 2026, El Niño is likely to emerge (61% chance) and persist through at least the end of 2026.