Relative sunshine duration are derived from daily 1 km resolution gridded dataset from the Swiss federal agency for meteorology and climate (MeteoSwiss) using a bilinear downscaling to 25 m resolution. Monthly and yearly individual year and current average (1981-2010) layers can be downloaded from separate zip files. No Future layers could be calculated since no scenario is available from the CH2018 initiative. The layer files are stored in compressed GeoTIFF format with the “deflate” algorithm with option “predictor2” from the GDAL. This format has a high compression ratio but allows direct import in most GIS softwares. All the maps are projected in the Swiss coordinate system CH 1903+ LV95 (epsg:2056) with a resolution of 25x25m using the extent of the digital height model DHM25 of the Swiss office for topography (swisstopo).