Frequently Asked Questions

Wave-model skill is high in the first 24 hours and decays with lead time — beyond about 5 days treat any surf forecast as a rough guide. We measure our own accuracy continuously by scoring every forecast against NOAA buoy observations and publish the results on our forecast accuracy page, including systematic bias by region and lead time.

Wave period is the time in seconds between successive wave crests. It is the best single indicator of surf quality: waves at 12 seconds or more are ground swell — organized, powerful lines from distant storms — while waves under 9 seconds are locally generated wind swell that breaks weak and crumbly. A 3 ft wave at 14 seconds usually beats a 5 ft wave at 7 seconds.

Ground swell (period 12s+) is generated by storms far away and arrives sorted into clean, evenly spaced sets. Wind swell (period under 9s) is generated by local wind and arrives disorganized and choppy. Mid-period swell (9–12s) sits in between and can be very fun at the right spots.

Offshore wind blows from the land out to sea, holding up wave faces so they break cleanly and slowly. Onshore wind pushes waves over early and chops up the surface. Light cross-shore wind is usually surfable. Our dashboard classifies wind automatically using each beach's facing direction.

It depends on the spot — many beach breaks favor mid tide with some water movement, while some reefs and points only work at specific stages. Moving water (an incoming or outgoing tide) generally beats slack tide. Our session planner factors tide movement into its hourly scores, and every forecast page shows the local NOAA tide curve.

Long-period swells from distant storms can be tracked 4–7 days out with decent confidence because the swell already exists and travels at a known speed. Local wind — which decides whether the surf is clean or blown out — is only reliable 1–3 days out. That is why our dashboard shows a confidence score that decays with lead time.

Yes. Strong storms over Lake Michigan, Superior, Erie, and Ontario produce rideable wind swell, mostly in fall and winter. The lakes are non-tidal, so forecasting reduces to wave height, period, and wind. We cover Great Lakes spots with the same wave models used for the coasts.

Forecast models report significant wave height — the average of the largest third of waves in open water — not the face height you see at the beach. Shoaling, refraction, and local bathymetry change what actually breaks; sets can run noticeably larger than the significant height. Treat forecast height as a consistent index, and learn how your local spot translates it.

Yes — every feature is free with no account, no paywall, and no ads. The site runs on free public data sources and is supported by donations. If it saves you a skunked session, you can buy us a coffee.

Waves come from NOAA's WaveWatch III / GFS-Wave models (via Open-Meteo and NOAA ERDDAP servers), wind and temperature from NOAA GFS, tides from NOAA CO-OPS reference stations, and real-time observations from NDBC and CDIP buoys. Everything is public, government-grade model output — the same underlying data paid apps use.

NOAA's wave models run every 6 hours, and the dashboard fetches fresh data on every page load. Buoy observations and tide predictions are live. There is no once-a-day human editorial cycle — what you see is the latest model run.

Surfline puts its 16-day forecasts, cam rewind, and most features behind a subscription. We show the full forecast, buoy data, tides, swell maps, and cams for free — but we do not have proprietary cameras or human forecasters. See the full comparison.

Yes — the dashboard shows nearby free cams (YouTube live streams and public webcams) for many spots, plus links to third-party cam networks where streaming is not permitted. Cam coverage grows continuously.

Yes. Every spot has a free embeddable forecast card — an iframe you can drop into any site, ideal for surf shops, schools, and beach-town pages. Open a spot's forecast page and use the embed link in the footer, or see an example spot page.