Abstract. Meteosat Second Generation (MSG) satellite images acquired every 15min during daytime are currently processed by the Heliosat-2 method every night to generate the HelioClim-3 (HC3) database of the surface solar irradiation for the day before. A new service is proposed based on version 4 of HC3 (HC3v4) that offers real-time and forecasted irradiation for horizons up to a few hours. The service is based on a local persistence of the clear-sky index. Its results were compared to coincident high quality 15min global irradiations measured in fourteen stations belonging to the Baseline Surface Radiation Network (BSRN). For forecasts for a temporal horizon of 15min ahead, the relative bias and root mean square error (RMSE) range respectively from 0 to 2%, and 20 to 23% for most stations. The correlation coefficient ranges from 0.94 to 0.95. These performances are similar to HC3v4 for the same stations. Expectedly, the quality of the forecasts degrades as the temporal horizon increases. For 1h ahead forecasts of 15min irradiation, the relative bias, root mean square error (RMSE) and correlation coefficient range respectively from −3 to 1%, 30 to 37%, and 0.90 to 0.91.