93% probability 2026 ranks among the three warmest calendar years on record in the Copernicus C3S (ERA5) dataset. 2026's months have ranked 2nd–5th warmest, leaving a comfortable buffer to 4th. Resolves ~Jan 2027 via the Copernicus annual highlights.
Through mid-2026, every month ranked 2nd–5th warmest on record (e.g., May 2026 = 2nd-warmest May at 15.81°C, +0.55°C vs the 1991–2020 mean). The ~0.25°C buffer between 3rd and 4th place dwarfs realistic late-2026 variability. Source: Copernicus C3S Global Climate Highlights 2026 (climate.copernicus.eu); resolves ~Jan 2027.
We lock a binary: 2026 ranks 1st, 2nd or 3rd warmest calendar year on record in the Copernicus Climate Change Service (ERA5) global dataset, per the official 2026 Global Climate Highlights. Confidence 93%.
2026's monthly anomalies have run consistently 2nd–5th warmest on record, sitting well above the 4th-place threshold; the ~0.25°C gap to 4th is far larger than the swing the back half of the year could plausibly produce. A top-3 finish would only fail on an abrupt, sustained cooling (a strong La Niña + volcanic forcing) with no historical precedent at this magnitude mid-year. Resolves against the Copernicus annual ranking.
RAOSCAFF locks P-87 on 2026-06-24. Scored on whether 2026 ranks 1st, 2nd or 3rd warmest calendar year in the Copernicus C3S (ERA5) global dataset.
Scored against one named dataset (Copernicus C3S/ERA5) to avoid cross-dataset ranking ambiguity.