Climate · 7 min
ENSO and the season ahead: what seasonal forecasts can and cannot tell you
At seasonal range the honest output is a probability shift, not a forecast. That is still worth a great deal if you price it correctly.
Ensemble Weather AI Research ·
The El Niño–Southern Oscillation is the single largest source of seasonal predictability on the planet. It is a coupled ocean–atmosphere pattern in the tropical Pacific, and its phase shifts the odds of rainfall and temperature anomalies across a large fraction of the globe months in advance.
What it does not do is tell you about a specific day. A seasonal forecast that claims to know next March's weather is selling something. What an honest seasonal product says is: this region's probability of a dry season has moved from 33% to 55%, with this much confidence, for this reason.
For an irrigation manager or a crop insurer, that shift is enormous — it is the difference between pricing a policy correctly and pricing it wrong across an entire book. For someone planning a wedding, it is worthless. Both facts are true at once, and the product should say so plainly.
We publish seasonal output as probabilistic briefings rather than per-call API responses, because the per-call framing invites exactly the misreading above. A briefing can carry the caveat in the same breath as the number.
Every response carries the spread
Ensemble members, model weights and p10/p50/p90 on every value — including on the free tier.