Forecast Verification
Swell Intel records every forecast before the swell arrives — snapshotted at a stated lead time — and scores it afterwards against what the station reported. That record publishes here openly, misses included, once it spans a full month of forecasts that carry wall-clock proof they were written down ahead of time.
The record is being built now — it isn't published yet.
Publishing a forecast track record only means something if every prediction in it was stored before its swell arrived. Swell Intel now stamps each forecast with a wall-clock timestamp at the moment it is recorded, so a prediction can be proven to pre-date the observation it is scored against. The record opens to the public the first time those wall-clock-proved forecasts span 30 distinct days — and it stays open from then on.
So far the forward-recorded forecasts cover 24 of 30 days and 16,889 predicted-vs-measured pairs are being held back until that threshold is reached. On current pace the record opens around September 9, 2026.
Why not show what we already have? An earlier batch of pairs was backfilled — reconstructed after the swells had already come and gone, with no timestamp proving the forecast pre-dated the measurement. Those rows are deliberately excluded: a track record you filled in after the fact isn't a track record. Only forecasts recorded live, ahead of time, will appear here, which is why the clock effectively starts now rather than in the past.
What will be published
When the record opens, it publishes the raw predicted-vs-measured pairs — per station and per lead time, misses included — as separate labelled series that are never pooled into one figure: sampled at the station itself or at the nearest surf spot, total height or swell partition only, instrument measurement or a clearly labelled model nowcast. No aggregate “overall accuracy” number is ever added; the individual pairs are the published artifact.
For how the forecasts are actually built in the meantime, read the forecasting methodology.
In the meantime, check the forecasts.
The verification record opens once it matures. Until then, browse the breaking-wave-height forecasts the record will be scoring.
Browse Forecasts