El Nino Peak NOV/DEC-26, La Nina Later Next Year

October 2026 Climate Impact Company ENSO Outlook

Issued: Tuesday October 13, 2026

Highlight: El Nino peak NOV/DEC-26, La Nina later next year. La Nina with +AMO brings a lot of North Atlantic hurricanes next year. Decade-long cool PDO ends later next year. +IOD peak next month; reversal to -IOD later 2027.

Discussion: The Climate Impact Company Nino34 analog forecast through FEB-28 reveals current observations are exceeding the historically most intense (Nino34) signatures (Fig. 1). El Nino 2026-27 will be record intense, peaking during DEC-26. El Nino intensity steadily decreases during Q1/2027 shifting to neutral phase by MAY-27. The outlook projects weak La Nina to follow mid-to-late 2027.

The multivariate ENSO index (MEI) outlook (also) indicates record intensity although less aggressive (Fig. 2). Peak intensity may occur prior to Nino34 (peak). MEI warm ENSO intensity lasts longer than Nino34, decelerating rapidly during the middle of next year with an equally quick transition into La Nina by July.

The Pacific decadal oscillation has been in the (cool) negative phase this entire decade. The Climate Impact Company analog forecast projects -PDO to slowly fade next year to neutral phase, for the first time this decade, by late 2027 (Fig. 3).

The Atlantic multi-decadal oscillation is in strong (warm) positive phase. The strong +AMO is very supportive of powerful tropical cyclones in the North Atlantic basin knocked down by El Nino wind shear during the 2026 season. The analog forecast reveals strong warm phase continues through 2027 (Fig. 4). With La Nina emerging next year, the warm North Atlantic and cool ENSO should combine for a robust 2027 hurricane season.

The Indian Ocean dipole (IOD) has shifted to strong positive phase likely to parallel the El Nino signal with intensification to peak during OCT/NOV-26 followed by steady weakening early in 2027 (Fig. 5). IOD shifts to negative phase with La Nina later 2027.

Fig. 1: Climate Impact Company Nino34 analog forecast through February 2028.

Fig. 2: Climate Impact Company multivariate ENSO index analog forecast through February 2028.

Fig. 3: Climate Impact Company Pacific decadal oscillation analog forecast through February 2028.

Fig. 4: Climate Impact Company Atlantic multi-decadal oscillation analog forecast through February 2028.

Fig. 5: Climate Impact Company Indian Ocean Dipole analog forecast through February 2028.