SwellOracle methodology
See how physical observations, model points and historical data are handled.
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Surf Buoy and Swell Data: Frequently Asked Questions
These answers explain what SwellOracle pages show, what they cannot tell you and how to use ocean data as part of a safer surf decision.
Is a surf buoy the same as a surf forecast?
No. A physical buoy is an instrument that reports conditions at its offshore location. A surf forecast is an estimate of conditions over a future time window. Both are useful, but they answer different questions.
Use the forecast to plan ahead and a recent observation to check whether the offshore signal is arriving. Neither replaces local wind, tide, beach conditions or official warnings.
Why does the beach look different from the buoy?
A buoy measures at one point offshore. Before waves reach the beach they can be changed by coastline angle, islands, headlands, depth, sandbars, wind, tide and currents.
Compare the buoy direction and period with the exposure of your beach. A valid buoy reading can still be a poor direct proxy for a sheltered or differently oriented spot.
What is the difference between a buoy and a marine model?
A buoy or station is a physical observation when the provider identifies an instrument in the water. A marine model estimates conditions for a geographic grid point using calculations and source data.
SwellOracle labels these source types separately. Model points can add regional context where public instruments are sparse, but they should not be presented as measured buoy readings.
How recent should a reading be?
The best answer depends on how quickly conditions are changing, but the observation time should always be visible before you compare stations. A stale reading can be background context; it should not be treated as the current sea state.
When two feeds update on different schedules, compare the newest observations that represent a similar time window rather than trusting a number only because it looks favorable.
Why is wind missing on some buoy pages?
Not every provider publishes wind with its wave data. If a station does not report wind, SwellOracle leaves it unavailable instead of inventing a value.
A clearly labelled model or local coastal observation may help provide wind context, but it remains a different source from the buoy's wave measurement.
Can I use SwellOracle for safety decisions?
No. SwellOracle is an informational tool. Check official marine warnings, local regulations, weather and visible conditions, and use your own judgement before entering the water.
Conditions can change quickly. A useful data workflow supports local awareness; it does not guarantee safe surf or safe navigation.
Practical takeaway
Read the source and timestamp first, then combine the offshore signal with local conditions and official information.