CHclim25 is a climatic dataset with a 25 m x 25 m resolution for Switzerland including monthly and yearly layers for temperature, precipitation, relative sunshine duration, growing degree days, potential evapotranspiration, bioclimatic variables and aridity. The dataset is derived from a daily 1 km resolution gridded dataset from the Swiss federal agency for meteorology and climate (MeteoSwiss) using a downscaling procedure based on local regressions with a 25 m resolution elevation model in order to better account for local topography and related complex local climatic phenomena. Climatic layers in a geoTIFF format are provided for the baseline 1981-2010 period as well as for three future periods (2020-2049, 2045-2074, and 2070-2099) incorporating three different circulation models (GCM-RCM) and three representative concentration pathways (RCPs) from the CH2018 initiative.