Recent observations show the 2026 El Niño rapidly intensifying, with weekly Niño 3.4 sea surface temperature anomalies reaching +2.7°C and 3-month means climbing above +2.0°C by late summer. NOAA’s Relative Oceanic Niño Index (RONI), which adjusts central Pacific anomalies relative to the broader tropics, underpins the market’s 62.5% implied probability for a peak exceeding 2.5°C. Multi-model ensembles project continued strengthening through a winter maximum near 3.0–3.6°C, driven by deep subsurface warming, persistent westerly wind anomalies, and enhanced convection. This aligns with NOAA’s >90% chance of a very strong event and 69% likelihood of surpassing the +2.5°C historic threshold in October–December. Lower-probability bins reflect residual uncertainty in exact peak timing and any late-season adjustments from evolving atmospheric coupling.
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 63%
2.25–2.5 20%
2.0–2.25 14.9%
1.5–2.0 3.3%
Under 1.5
<1%
1.5–2.0
3%
2.0–2.25
15%
2.25–2.5
20%
Over 2.5
63%
Over 2.5 63%
2.25–2.5 20%
2.0–2.25 14.9%
1.5–2.0 3.3%
Under 1.5
<1%
1.5–2.0
3%
2.0–2.25
15%
2.25–2.5
20%
Over 2.5
63%
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 observations show the 2026 El Niño rapidly intensifying, with weekly Niño 3.4 sea surface temperature anomalies reaching +2.7°C and 3-month means climbing above +2.0°C by late summer. NOAA’s Relative Oceanic Niño Index (RONI), which adjusts central Pacific anomalies relative to the broader tropics, underpins the market’s 62.5% implied probability for a peak exceeding 2.5°C. Multi-model ensembles project continued strengthening through a winter maximum near 3.0–3.6°C, driven by deep subsurface warming, persistent westerly wind anomalies, and enhanced convection. This aligns with NOAA’s >90% chance of a very strong event and 69% likelihood of surpassing the +2.5°C historic threshold in October–December. Lower-probability bins reflect residual uncertainty in exact peak timing and any late-season adjustments from evolving atmospheric coupling.
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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