The inslation within a single day on a horizontla plane as a result of Points Solar Radiation tool gives around 2 hours less sunshine hours, compared to long-term average from local meteostation and also compared to data from PVGIS, and also to extraterestrial insolation. I tested several days within a year (20th, 60th, 180th) with similar results. I also tried to increase the "diffusion proportion parameter" to get an earlier-morning and late-evening insolation, but this only increased the total insolation, remaining the first and last insolation hour of the day the same. The location is the city of Prague, 14.42°E, 50.08°N.
Thanks for any advise.
