Legal
Data attributions
Offwind is built almost entirely on public data. These are the sources, and the terms they come with.
Forecast models
US National Oceanic and Atmospheric Administration, National Centers for Environmental Prediction. Produced by a US Government agency and in the public domain. NOAA does not endorse this site and is not responsible for anything derived from the data.
European Centre for Medium-Range Weather Forecasts. This data and the products derived from it here are based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF). Licensed under CC BY 4.0 and the ECMWF Terms of Use. ECMWF does not accept liability for any error or omission in the data, for its availability, or for any loss or damage arising from its use. Forecasts shown here are modified from the ECMWF open data release by extraction to a route corridor and recompression.
Historical reanalysis data, read from the ARCO-ERA5 mirror of the Copernicus Climate Data Store. Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains. Modified here by extraction to a route corridor and recompression.
Bathymetry and charting
Global ocean bathymetry. Cited as: GEBCO Compilation Group (2024) GEBCO 2024 Grid (doi:10.5285/1c44ce99-0a0d-5f4f-e063-7086abc0ea0f).
Per-lake depth grids. Lake depth comes from this source.
Electronic Navigational Chart Approach, Harbour and Berthing feature services, used for inshore depth contours. These are chart products reprocessed for planning; they are not a substitute for official charts and carry no navigational warranty here.
Shoreline data derived from OpenStreetMap, which also underlies the base map. © OpenStreetMap contributors, available under the Open Database Licence.
The base map style and vector tiles the chart is drawn from, built on OpenStreetMap data.
Tidal currents
Tidal current predictions are computed by RegattaPages from the ADCIRC regional tidal constituent databases EC2015 (Western North Atlantic, Caribbean and Gulf of Mexico) and ENPAC15 (Eastern North Pacific), obtained from the ADCIRC website. These databases were developed at the University of Oklahoma with support from the National Oceanic and Atmospheric Administration (EC2015) and the U.S. Army Corps of Engineers Institute of Water Resources and Engineer Research and Development Center (ENPAC15). The predictions presented here are derived products computed by RegattaPages. They are not official NOAA, USACE, or ADCIRC products, and RegattaPages is not affiliated with, operated by, or endorsed by NOAA, the U.S. Army Corps of Engineers, the University of Oklahoma, or the ADCIRC development team. The database authors and the U.S. Army Corps of Engineers assume no responsibility for their accuracy. Some constituents are used with the caution the authors advise. Not for navigation. Cited as: Szpilka, C.; Dresback, K.; Kolar, R.; Feyen, J.; Wang, J. Improvements for the Western North Atlantic, Caribbean and Gulf of Mexico ADCIRC Tidal Database (EC2015). J. Mar. Sci. Eng. 2016, 4(4), 72 (doi:10.3390/jmse4040072); and Szpilka, C.; Dresback, K.; Kolar, R.; Massey, T.C. Improvements for the Eastern North Pacific ADCIRC Tidal Database (ENPAC15). J. Mar. Sci. Eng. 2018, 6(4), 131 (doi:10.3390/jmse6040131).
Coastal and Great Lakes current forecasts from the NOAA National Ocean Service, read from the NOAA Open Data Dissemination program. Produced by a US Government agency and in the public domain; NOAA does not endorse this site.
Astronomical arguments used in tidal predictions. MIT License, © 2017 Tyler C. Sutterley. Permission is hereby granted, free of charge, to any person obtaining a copy of this software, to deal in the Software without restriction; the software is provided “as is”, without warranty of any kind.
Boat performance
ORC certificate data is used to set boat performance. ORC does not endorse this site, and a route computed here has no standing under any rating rule.
Network data
Which network an address belongs to, used only to pace automated traffic; addresses are not stored. By Frank Denis, dedicated to the public domain.
A list of hosting and datacenter networks. MIT License, © 2025 Brian Hamachek. Permission is hereby granted, free of charge, to any person obtaining a copy of this software, to deal in the Software without restriction; the software is provided “as is”, without warranty of any kind.
Cloud ranges published by Amazon Web Services, Google Cloud, Microsoft Azure, Oracle Cloud, DigitalOcean, Linode and Vultr; iCloud Private Relay egress ranges published by Apple, so its users are never treated as automated; and the Tor Project’s exit list.
Software
The map renderer, under the 3-Clause BSD licence.
The single-file tile archive format the chart and bathymetry are served from, under the BSD-3-Clause licence.
If you maintain one of these datasets and the attribution here is wrong or insufficient, tell me and it will be corrected.