Terms of Use & Data Sources
Last updated: 27 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.
Tropical cyclones. The storm tracks and cones shown in the app are guidance drawn from NOAA/NHC advisories and ECMWF open data model tracks — not an official warning. Systems reported only by the ECMWF model are model guidance, not an advisory. Always follow the official warnings for your area.
This notice is reachable at any time from the app's 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 access to this site — scraping, bulk downloading or mirroring its forecast files — is not permitted. Developers: derived forecasts are available through our keyed API under the API terms.
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 Predict Sea.
- ECMWF IFS & AIFS — This service is based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF). This ECMWF data is published under a Creative Commons Attribution 4.0 International (CC BY 4.0). Source: www.ecmwf.int; terms of use: ECMWF open data licence. Contains modified ECMWF data, © 2026 European Centre for Medium-Range Weather Forecasts (ECMWF). ECMWF does not accept any liability whatsoever for any error or omission in the data, their availability, or for any loss or damage arising from their use.
- ICON, ICON-EU, GWAM, EWAM — Deutscher Wetterdienst (DWD), CC BY 4.0. DWD open data licensed under CC BY 4.0, modified 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; modified by Predict Sea. ECCC does not endorse Predict Sea.
- 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 (© 2026 European Centre for Medium-Range Weather Forecasts (ECMWF), 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.
Predict Sea modifies every model's output: fields are cropped, regridded to regular latitude-longitude grids where needed, converted to display units, quantised and re-encoded as Predict Sea grid and point files, and some are derived (for example rain rate from accumulated precipitation). The upstream agencies are not responsible for this presentation.
If you reproduce a chart from this site, please carry this line with it (the per-model credits, licences and statements above are also published machine-readable as attribution.json):
Chart: Predict Sea (predictsea.com). Forecast data: NOAA NCEP (public domain); contains modified ECMWF data, © 2026 European Centre for Medium-Range Weather Forecasts (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 (© 2026 European Centre for Medium-Range Weather Forecasts (ECMWF), 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.
Contact: predictsea@outlook.com