Through April, the international model guidance was pointing to a moderate-to-strong El Niño event peaking in late December 2026 or early January 2027. The early May 2026 European model run has shifted the picture. The central case has firmed toward a strong event, with the Niño 3.4 sea-surface temperature plume now tracking toward a peak near +3°C — putting the event in the same category as 1972-73, 1997-98 and 2015-16 at peak amplitude.

Atmospheric coupling is also appearing earlier than expected, with the spring 2026 pattern projected as a structurally classical El Niño spring. Eastern New Zealand — Canterbury, Hawke's Bay, Gisborne, Marlborough, Wairarapa and inland Otago — faces elevated drought risk, frequent foehn (NW) wind events, and a higher probability of extreme heat through summer. West Coast and western North Island operators face the opposite problem — excess moisture and compressed weather windows. The window for low-cost preparation runs from now through to August.