**Strong model consensus and official NOAA forecasts for a record-strength 2026–27 El Niño drive the 68.5% market-implied odds of peak RONI exceeding 2.5°C.** El Niño conditions have strengthened rapidly since mid-2026, with current weekly Niño 3.4 anomalies near +2.6°C and atmospheric coupling consistent with a very strong event. NOAA’s August outlook assigns >90% probability of a very strong episode (RONI ≥2.0°C) through winter 2026–27 and specifically 69% odds that the October–December 3-month RONI reaches or exceeds +2.5°C—surpassing prior events since 1950 on the relative index that isolates the ENSO signal from background tropical warming. WMO’s early September update echoes near-100% persistence and further intensification toward year-end. Traders appear to weight these dynamical and statistical model runs heavily, with only modest probability assigned to lower peaks that would require substantial forecast revisions in coming months.
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 69%
2.25–2.5 28%
2.0–2.25 4.3%
1.5–2.0 <1%
$24,052 Vol.
$24,052 Vol.
Under 1.5
<1%
1.5–2.0
1%
2.0–2.25
4%
2.25–2.5
28%
Over 2.5
69%
Over 2.5 69%
2.25–2.5 28%
2.0–2.25 4.3%
1.5–2.0 <1%
$24,052 Vol.
$24,052 Vol.
Under 1.5
<1%
1.5–2.0
1%
2.0–2.25
4%
2.25–2.5
28%
Over 2.5
69%
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...**Strong model consensus and official NOAA forecasts for a record-strength 2026–27 El Niño drive the 68.5% market-implied odds of peak RONI exceeding 2.5°C.** El Niño conditions have strengthened rapidly since mid-2026, with current weekly Niño 3.4 anomalies near +2.6°C and atmospheric coupling consistent with a very strong event. NOAA’s August outlook assigns >90% probability of a very strong episode (RONI ≥2.0°C) through winter 2026–27 and specifically 69% odds that the October–December 3-month RONI reaches or exceeds +2.5°C—surpassing prior events since 1950 on the relative index that isolates the ENSO signal from background tropical warming. WMO’s early September update echoes near-100% persistence and further intensification toward year-end. Traders appear to weight these dynamical and statistical model runs heavily, with only modest probability assigned to lower peaks that would require substantial forecast revisions in coming months.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated


Beware of external links.
Beware of external links.
Frequently Asked Questions