API Response
Data Sources
The Marine API combines wave models from different sources.
| Data Set | Region | Spatial Resolution | Temporal Resolution | Data Availability | Update frequency | |
|---|---|---|---|---|---|---|
| MeteoFrance MFWAM | Global | Map | 0.08° (~8 km) | 3-Hourly | October 2021 with 10 day forecast | Every 12 hours |
| MeteoFrance SMOC Currents | Global | Map | 0.08° (~8 km) | Hourly | January 2022 with 10 day forecast | Every 24 hours |
| ECMWF WAM | Global | 0.25° (~25 km) | 3-Hourly | March 2024 with 10 day forecast | Every 6 hours | |
| NCEP GFS Wave | Global | 0.25° (~25 km) | Hourly | June 2024 with 16 day forecast | Every 6 hours | |
| DWD GWAM | Europe | 0.05° (~5 km) | Hourly | August 2022 with 8 day forecast | Twice daily | |
| DWD EWAM | Global | 0.25° (~25 km) | Hourly | August 2022 with 4 day forecast | Twice daily | |
| ERA5-Ocean | Global | 0.5° (~50 km) | Hourly | 1940 to present | Daily with 5 days delay |
API Documentation
The API endpoint /v1/marine accepts a geographical coordinate, a list of marine variables and responds with a JSON hourly marine weather forecast for 7 days. Time always starts at 0:00 today. All URL parameters are listed below:
| Parameter | Format | Required | Default | Description |
|---|---|---|---|---|
| latitude, longitude | Floating point | Yes | Geographical WGS84 coordinates of the location. Multiple coordinates can be comma separated. E.g. &latitude=52.52,48.85&longitude=13.41,2.35. To return data for multiple locations the JSON output changes to a list of structures. CSV and XLSX formats add a column location_id. | |
| hourly | String array | No | A list of weather variables which should be returned. Values can be comma separated, or multiple &hourly= parameter in the URL can be used. | |
| daily | String array | No | A list of daily weather variable aggregations which should be returned. Values can be comma separated, or multiple &daily= parameter in the URL can be used. If daily weather variables are specified, parameter timezone is required. | |
| current | String array | No | A list of variables to get current conditions. | |
| timeformat | String | No | iso8601 | If format unixtime is selected, all time values are returned in UNIX epoch time in seconds. Please note that all timestamp are in GMT+0! For daily values with unix timestamps, please apply utc_offset_seconds again to get the correct date. |
| timezone | String | No | GMT | If timezone is set, all timestamps are returned as local-time and data is returned starting at 00:00 local-time. Any time zone name from the time zone database is supported. If auto is set as a time zone, the coordinates will be automatically resolved to the local time zone. For multiple coordinates, a comma separated list of timezones can be specified. |
| past_days | Integer (0-92) | No | 0 | If past_days is set, yesterday or the day before yesterday data are also returned. |
| forecast_days | Integer (0-8) | No | 5 | Per default, 7 days are returned. Up to 8 days of forecast are possible. |
| forecast_hours past_hours | Integer (>0) | No | Similar to forecast_days, the number of timesteps of hourly data can controlled. Instead of using the current day as a reference, the current hour is used. | |
| start_date end_date | String (yyyy-mm-dd) | No | The time interval to get weather data. A day must be specified as an ISO8601 date (e.g. 2022-06-30). | |
| start_hour end_hour | String (yyyy-mm-ddThh:mm) | No | The time interval to get weather data for hourly data. Time must be specified as an ISO8601 date (e.g. 2022-06-30T12:00). | |
| length_unit | String | No | metric | Options metric and imperial |
| cell_selection | String | No | sea | Set a preference how grid-cells are selected. The default land finds a suitable grid-cell on land with similar elevation to the requested coordinates using a 90-meter digital elevation model. sea prefers grid-cells on sea. nearest selects the nearest possible grid-cell. |
| apikey | String | No | Only required to commercial use to access reserved API resources for customers. The server URL requires the prefix customer-. See pricing for more information. |
Additional optional URL parameters will be added. For API stability, no required parameters will be added in the future!
Hourly Parameter Definition
The parameter &hourly= accepts the following values. Most weather variables are given as an instantaneous value for the indicated hour. Some variables like precipitation are calculated from the preceding hour as an average or sum.
| Variable | Valid time | Unit | Description |
|---|---|---|---|
| wave_height wind_wave_height swell_wave_height | Instant | Meter | Wave height of significant mean, wind and swell waves. Wave directions are always reported as the direction the waves come from. 0° = From north towards south; 90° = From east |
| wave_direction wind_wave_direction swell_wave_direction | Instant | ° | Mean direction of mean, wind and swell waves |
| wave_period wind_wave_period swell_wave_period | Instant | Seconds | Period between mean, wind and swell waves. |
| wind_wave_peak_period swell_wave_peak_period | Instant | Seconds | Peak period between wind and swell waves. |
| ocean_current_velocity | Instant | km/h (mph, m/s, knots) | Velocity of ocean current considering Eulerian, Waves and Tides. |
| ocean_current_direction | Instant | ° | Direction following the flow of the current. E.g. where the current is heading towards. 0° = Going north; 90° = Towards east. |
Daily Parameter Definition
Aggregations are a simple 24 hour aggregation from hourly values. The parameter &daily= accepts the following values:
| Variable | Unit | Description |
|---|---|---|
| wave_height_max wind_wave_height_max swell_wave_height_max | Meter | Maximum wave height on a given day for mean, wind and swell waves |
| wave_direction_dominant wind_wave_direction_dominant swell_wave_direction_dominant | ° | Dominant wave direction of mean, wind and swell waves |
| wave_period_max wind_wave_period_max swell_wave_period_max | Seconds | Maximum wave period of mean, wind and swell |
| wind_wave_peak_period_max swell_wave_peak_period_max | Seconds | Maximum peak period between wind and swell waves. |
JSON Return Object
On success a JSON object will be returned.
"latitude": 52.52,
"longitude": 13.419,
"elevation": 44.812,
"generationtime_ms": 2.2119,
"utc_offset_seconds": 0,
"timezone": "Europe/Berlin",
"timezone_abbreviation": "CEST",
"hourly": {
"time": ["2022-07-01T00:00", "2022-07-01T01:00", "2022-07-01T02:00", ...],
"wave_height": [1, 1.7, 1.7, 1.5, 1.5, 1.8, 2.0, 1.9, 1.3, ...]
},
"hourly_units": {
"wave_height": "m"
},
| Parameter | Format | Description |
|---|---|---|
| latitude, longitude | Floating point | WGS84 of the center of the weather grid-cell which was used to generate this forecast. This coordinate might be a few kilometers away from the requested coordinate. |
| generationtime_ms | Floating point | Generation time of the weather forecast in milliseconds. This is mainly used for performance monitoring and improvements. |
| utc_offset_seconds | Integer | Applied timezone offset from the &timezone= parameter. |
| timezone timezone_abbreviation | String | Timezone identifier (e.g. Europe/Berlin) and abbreviation (e.g. CEST) |
| hourly | Object | For each selected weather variable, data will be returned as a floating point array. Additionally a time array will be returned with ISO8601 timestamps. |
| hourly_units | Object | For each selected weather variable, the unit will be listed here. |
| daily | Object | For each selected daily weather variable, data will be returned as a floating point array. Additionally a time array will be returned with ISO8601 timestamps. |
| daily_units | Object | For each selected daily weather variable, the unit will be listed here. |
Errors
In case an error occurs, for example a URL parameter is not correctly specified, a JSON error object is returned with a HTTP 400 status code.
"error": true,
"reason": "Cannot initialize WeatherVariable from invalid String value tempeture_2m for key hourly"
Citation & Acknowledgement
Generated using ICON Wave forecast from the German Weather Service DWD.
All users of Open-Meteo data must provide a clear attribution to DWD as well as a reference to Open-Meteo.