Recent NOAA Climate Prediction Center diagnostics show the 2026 El Niño strengthening rapidly, with July Niño-3.4 anomalies already at +2.7°C and RONI values climbing toward strong thresholds amid substantial subsurface heat content. Official August 2026 outlooks assign greater than 90% probability of a very strong event (RONI at or above +2.0°C) during fall and winter, including a 69% chance that the October-December peak exceeds the +2.5°C historic benchmark used in market resolution. Multi-model ensembles from CPC, IRI, and JMA converge on maximum intensity in the OND 2026 window, driven by persistent atmosphere-ocean coupling and minimal tropical-mean subtraction in the RONI calculation. These verified observational and forecast signals underpin trader consensus favoring the Over 2.5 outcome at current implied probabilities.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedWhat will the peak RONI be for the 2026–27 El Niño?
Over 2.5 65%
2.25–2.5 20%
2.0–2.25 16.2%
Under 1.5 <1%
Under 1.5
<1%
1.5–2.0
<1%
2.0–2.25
16%
2.25–2.5
20%
Over 2.5
65%
Over 2.5 65%
2.25–2.5 20%
2.0–2.25 16.2%
Under 1.5 <1%
Under 1.5
<1%
1.5–2.0
<1%
2.0–2.25
16%
2.25–2.5
20%
Over 2.5
65%
The peak RONI is 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 reported in official NOAA CPC RONI updates (https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/).
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.
Market Opened: Aug 17, 2026, 3:17 PM ET
Resolver
0x69c47De9D...The peak RONI is 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 reported in official NOAA CPC RONI updates (https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso/roni/).
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.
Resolver
0x69c47De9D...Recent NOAA Climate Prediction Center diagnostics show the 2026 El Niño strengthening rapidly, with July Niño-3.4 anomalies already at +2.7°C and RONI values climbing toward strong thresholds amid substantial subsurface heat content. Official August 2026 outlooks assign greater than 90% probability of a very strong event (RONI at or above +2.0°C) during fall and winter, including a 69% chance that the October-December peak exceeds the +2.5°C historic benchmark used in market resolution. Multi-model ensembles from CPC, IRI, and JMA converge on maximum intensity in the OND 2026 window, driven by persistent atmosphere-ocean coupling and minimal tropical-mean subtraction in the RONI calculation. These verified observational and forecast signals underpin trader consensus favoring the Over 2.5 outcome at current implied probabilities.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated


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