- Will the peak RONI for the 2026–27 El Niño be below 1.5?<1¢
- Will the peak RONI for the 2026–27 El Niño be at least 1.5 but below 2.0?<1¢
- Will the peak RONI for the 2026–27 El Niño be at least 2.0 but below 2.25?13¢
- Will the peak RONI for the 2026–27 El Niño be at least 2.25 but below 2.5?20¢
- Will the peak RONI for the 2026–27 El Niño be 2.5 or above?63¢
This market resolves based on the peak RONI — the single highest Regional Ocean Niño Index (RONI) value reported by NOAA's Climate Prediction Center (CPC) across the overlapping three-month seasons ASO 2026, SON 2026, OND 2026, NDJ 2026-27, and DJF 2026-27, as published in official NOAA CPC RONI updates (https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/). See each individual market for its bracket and full resolution terms. This market may resolve immediately once NOAA has published a RONI value that determines the peak: the "Over 2.5" outcome resolves "Yes" as soon as any listed season reaches +2.5°C or above. Any other outcome will not be confirmed until NOAA publishes the DJF 2026-27 value, since RONI can still rise in a later season and DJF captures El Niño's typical peak-strength window. The first published RONI value for each listed season is final and governs resolution; no subsequent revision to a season's value will change the outcome once that season's first value has been published. If CPC's RONI dataset is permanently discontinued, other information from NOAA may be used.
Recent observations show the 2026 El Niño already intensifying rapidly, with weekly Niño 3.4 sea surface temperature anomalies reaching +2.7°C by mid-August and seasonal means exceeding +2.0°C. NOAA’s Relative Oceanic Niño Index (RONI), which normalizes anomalies against broader tropical warming, underpins the market’s heavy weighting toward peaks over 2.5°C. Dynamical model ensembles project a median October–December RONI near +2.66°C, driven by exceptional upper-ocean heat content and sustained westerly wind bursts. This consensus, reinforced by over 90% probability of a very strong event through winter 2026–27, explains the 62.5% implied probability for outcomes above 2.5 while assigning minimal odds to weaker thresholds. Upcoming seasonal updates from the Climate Prediction Center will refine these ranges as the peak window approaches.