The bars show the chance of El Niño (red bars), ENSO-Neutral (grey bars), and La Niña (blue bars) provided for 9 upcoming, overlapping 3-month seasons (each letter represents a month, for example, F = February). Alternatively, the table presents the percent chances in numerical form.
Updates on the 2nd Thursday of each month associated with the ENSO Diagnostics Discussion.
The official outlook is determined by a ~10 member team, using available insights from multiple models (multi-model ensembles) and the latest observations using climate reanalysis, in situ measurements, and satellite data.
Probabilities are verified using the Relative Oceanic Niño Index (RONI), with El Niño and La Niña defined using -/+ 0.5 degree Celsius thresholds in sea surface temperature departures averaged in the Niño-3.4 region of the east-central equatorial Pacific Ocean (170–120W, 5S–5N). The 1991–2020 climatological base period is used to define the departures.
A 0% chance is approximate and not exact, meaning there is still some finite, non-zero chance (e.g. .01%) of the outcome occurring.
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