How can I query the current and forecasted temperatures at 3 locations?
The most commonly used temperature parameter is t_2m:C, which describes the temperature 2 meters above ground. For other available parameters, check Available Parameters.
Define a list of (latitude, longitude) pairs describing your locations by concatenating them with a '+' symbol, e.g. 47.42,9.38+47.37,8.46+52.50,13.35. For a detailed description of the accepted coordinates, check Coordinates Description.
The time must be encoded according to the ISO standard, e.g., from last midnight to 2 days into the future in 6 hour steps would be __replace__0T00:00:00ZP2D:PT6H. For a detailed description, check Time Description.
Choose a format, such as csv. For a description of all available formats, check Available Formats.
How can I display a simple weather symbol for tomorrow's general weather state?
There is a parameter for that: weather_symbol_12h:idx. It delivers an index that you can map to images you find here. The index describes the general weather state over the last 12h before the queried date.
Usually, to describe the daily weather state, the time between 6 and 18 o'clock is considered, so you should query the weather_symbol_12h:idx at 18 o'clock. For a detailed description of the required parameters, check Required Parameters
How can I query the wave heights for a whole region?
Check which parameter is of interest for you in the list of available marine parameters, e.g. significant_wave_height:m
Define the area you are interested in. You can use shortcuts such as north-atlantic:0.1,0.1 or specify a rectangular grid, as described in Coordinate Description. Note that when using shortcuts, you still need to define a resolution. This can be done with the area requests option.
Define a date you are interested in. Please note that for grids you can only choose one date and not a time series (with the exception of the format netcdf, which allows for gridded time series). Again, you can use shortcuts such as now or the ISO format, as described in Time Description.
I received strange values, e.g. -888. What does that mean?
There are some reserved parameters we use to tell you that the data is not valid. These are listed here: Reserved Values
What is the convention for wind, wave and ocean directions?
We are using the meteorological convention for all direction parameters.
The meteorological convention is that U component is positive for a west to east flow (e.g. eastward wind) and the V component is positive for south to north flow (e.g. northward wind). The wind_dir:d parameters are from 0° to 360°, where 0° means northerly wind (blowing from north to south) and 90° means easterly wind (blowing from east to west).
We are also using the meteorological convention for wave directions and ocean current directions. Meaning if e.g. mean_direction_wind_waves:d shows 180°, the waves travel from south to north.
Where is the data coming from?
In case you don't specify a certain model, we combine several models and techniques. You will receive the best available forecast for the queried date and location. That can be model output, satellite based, measured, radar based, etc.
Let's look at precipitation as an example:
For historic dates, such as those in 1980, precipitation data originates from a reanalysis model.
More recent data (from about 2015 to the present) originates from high resolution precipitation radars, if they are available for the particular location. If not, data is obtained from high resolution models, such as the ukmo-euro4.
Near future data, up to about two hours from the time of the request, is still derived from radar measurements; however, it is forecasted using a nowcast technique.
Medium range forecasts are also derived from high resolution models.
What is the reference coordinate system used?
All coordinates are in latitude/longitude pairs according to WGS84. The vertical datum is the EGM96 Geoid.
Is it possible to check how many queries have been sent from my account?