Cycle forecasts

To download a data file, select the file in the fold-down list by clicking on the corresponding gray TXT button. All files are in ASCII text and can be opened in any text editor. CSV files allow direct import in various applications, like spreadsheets.The INFO button gives a description of the contents of each file, and the corresponding time series can be viewed by clicking on the PLOT button.

12-month forecasts of the monthly sunspot number

  • Standard curves method (Waldmeier)
  • Combined method (Denkmayr - Cugnon)
  • Improved standard method prediction (Kalman)
  • Improved combined method prediction (Kalman)
  • Improved McNish & Lincoln method prediction (Kalman)
  • Data Credits: The Sunspot Number data can be freely downloaded. However, we request that proper credit to the WDC-SILSO is explicitely included in any publication using our data (paper article or book, on-line Web content, etc.), e.g.: "Source: WDC-SILSO, Royal Observatory of Belgium, Brussels".


    For additonal information, contact Frédéric Clette (E_mail: Frederic.Clette@oma.be )
    Royal Observatory of Belgium Av. Circulaire, 3 - B-1180 Brussels, Belgium