Once you've made your request for historical data and the request is completed, the data will be available in .csv format which you can access from the Solcast API Toolkit, or you can download from the confirmation email we send to you.

Depending on the parameters you selected when making the request, the .csv file may have different columns listed in the .csv file.

For all historical requests, the following is a list describing the columns that will always appear in your .csv file:

  1. Period End: The date of the measurement in UTC
  2. Period: The interval of the measurement in ISO 8601 standard (i.e. PT5M = 5 minutes)

Then, depending on the parameters you chose in your historical request, the following is a list describing the columns that may appear in your .csv file:

  1. Global Horizontal Irradiance (GHI, W/m2): The total irradiance received on a horizontal surface. It is the sum of the horizontal components of direct (beam) and diffuse irradiance.
  2. Direct (Beam) Horizontal Irradiance (EBH, W/m2): The horizontal component of Direct Normal Irradiance.
  3. Direct Normal Irradiance (DNI, W/m2): Solar irradiance arriving in a direct line from the sun as measured on a surface held perpendicular to the sun.
  4. Diffuse Horizontal Irradiance (DIF, DHI, W/m2): The horizontal component of diffuse irradiance (irradiance that is scattered by the atmosphere).
  5. Temperature (TEMP, Celcius): The temperature of the air in the given location (10 meters above ground level).
  6. Solar Zenith (degrees): The angle between a line perpendicular to the earth's surface and the sun (90 deg = sunrise and sunset; 0 deg = sun directly overhead).
  7. Solar Azimuth (degrees): The angle between a line pointing due north to the sun's current position in the sky. Negative to the East. Positive to the West. 0 at due North.
  8. Cloud Opacity (%): The measurement of how opaque the clouds are to solar radiation in the given location.
  9. Dewpoint (DWPT, Celsius): The air dewpoint temperature (2 meters above ground level).
  10. Relative Humidity (RH, %): The air relative humidity (2 meters above ground level).
  11. Surface Pressure (AP, hPa): The air pressure at ground level.
  12. Wind Speed (WS, m/s): The wind speed (10 meters above ground level).
  13. Wind Direction (WD, degrees): The wind direction (10 meters above ground level). This is the meteorological convention. 0 is a northerly (from the north); 90 is an easterly (from the east); 180 is a southerly (from the south); 270 is a westerly (from the west)
  14. Precipitable Water (PWAT, kg/m2): The total column preciptable water content.
  15. Snow depth (SWDE, cm): The snow depth liquid-water-equivalent.
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