Terms of Use & Data Sources
Last updated: 13 September 2026
Safety at sea — read this first
Forecast guidance only — not for navigation.
Always check official marine warnings before and during a passage.
Predict Sea provides guidance for passage planning only. Weather
forecasts are inherently uncertain; the models shown here are automated, unedited
computer output, and this site may contain delays, gaps, or errors — a run can be
hours old and is marked as such, but it is still a forecast, not an observation. It is
not a substitute for official meteorological warnings, navigational judgement,
or good seamanship. Before and during any voyage, always consult the official
marine forecasts and warnings issued by the national meteorological and hydrographic
authorities responsible for your area (in the US: NWS/NHC; internationally: the
WMO/IMO GMDSS METAREA services), and comply with SOLAS and your flag state's
requirements. Never make safety-critical decisions based on this site alone.
The short form of this notice is shown once inside the app the first time you open it; you can dismiss it, and it stays reachable from the info menu under Safety notice.
No warranty
This service is provided "as is", without warranty of any kind, express or implied, including fitness for a particular purpose. To the maximum extent permitted by law, 19 Lat accepts no liability for any loss or damage — including loss of life, injury, or damage to vessels or property — arising from use of, or inability to use, this site or its data.
Acceptable use
You may use the charts and images for personal and internal business purposes with attribution to Predict Sea. Automated bulk scraping of the data feed is not permitted; the upstream sources below offer far better channels for that. If you want to read our files programmatically, the format is documented in the project's data contract and we ask that you respect the cache headers.
Sponsors
Clearly labelled sponsor slots may appear in the app. Sponsors have no influence over the forecasts, models, freshness rules or wording shown here; the programme's rules and the current list are on the Sponsors page.
Data sources & attribution
- GFS, GFS-Wave, GEFS, RTOFS, HRRR, NAM — NOAA / National Centers for Environmental Prediction (NCEP), United States. US Government work, public domain. NOAA does not endorse this site.
- ECMWF IFS & AIFS — generated using ECMWF open data. Contains modified ECMWF data, © ECMWF, licensed under CC BY 4.0. ECMWF does not accept responsibility for any use of its data on this site.
- ICON, ICON-EU, GWAM, EWAM — Deutscher Wetterdienst (DWD), CC BY 4.0. DWD open data licensed under CC BY 4.0, modified (regridded and compressed) by Predict Sea.
- GDPS, GDWPS — Data Source: Environment and Climate Change Canada. Redistributed under the Environment and Climate Change Canada Data Servers End-use Licence; regridded and compressed by Predict Sea. ECCC does not endorse this site.
- Buoy observations — NOAA NDBC buoy observations (public domain; third-party stations credited by owner). Shown as observed at the station's anemometer height, not as a 10 m wind.
- Tropical cyclone tracks — NOAA/NHC tropical cyclone advisories; ECMWF open data tropical cyclone tracks (CC BY 4.0, contains modified ECMWF data) — guidance, not an official warning. Systems reported only by the ECMWF model are labelled as model guidance; always check the official warnings for your area.
- Coastlines, bathymetry, place & sea names, ports, country borders — Natural Earth (public domain).
- Detailed coastlines (regional zoom) — derived from OpenStreetMap land polygons, © OpenStreetMap contributors, ODbL. The derived per-region files are served from this site under the same licence.
- Maritime boundaries (EEZ, median and treaty lines) — Flanders Marine Institute (2023), Maritime Boundaries Geodatabase, version 12, available online at marineregions.org, licensed CC BY 4.0. Lines are generalised for display and are indicative only: they are not an official statement of any boundary and must not be used for navigation or legal purposes.
- Seamarks overlay (buoys, lights, beacons) — © OpenSeaMap contributors, data from OpenStreetMap under the ODbL. Crowd-sourced and unverified: not a substitute for official charts.
Model output shown here is post-processed (regridded, quantized, and rendered) by Predict Sea; the upstream agencies are not responsible for this presentation. Radar, satellite imagery and lightning detection are out of scope for this site: it is a static pipeline with no request-time backend, and those products need one.
If you reproduce a chart from this site, please carry this line with it:
Chart: Predict Sea (predictsea.com). Forecast data: NOAA NCEP (public domain); contains modified ECMWF data © ECMWF (CC BY 4.0); Deutscher Wetterdienst (DWD), CC BY 4.0, modified by Predict Sea; Data Source: Environment and Climate Change Canada. Observations: NOAA NDBC buoy observations (public domain; third-party stations credited by owner). Storm tracks: NOAA/NHC tropical cyclone advisories; ECMWF open data tropical cyclone tracks (CC BY 4.0, contains modified ECMWF data) — guidance, not an official warning. Basemap: Natural Earth; coastlines © OpenStreetMap contributors (ODbL); maritime boundaries Flanders Marine Institute 2023 (CC BY 4.0).
About
Predict Sea is made by 19 Lat. © 2026 19 Lat. All rights reserved for the site's own design and code; data remains under its upstream licences listed above.