CHclim25 – a spatially and temporally very high-resolution climatic dataset for Switzerland

Abstract. CHclim25 is a climatic dataset with a 25 m resolution for Switzerland that includes daily, monthly and yearly layers for temperature, precipitation, relative sunshine duration, growing degree-days, potential evapotranspiration, bioclimatic variables and aridity. The dataset is downscaled from a daily 1 km resolution dataset from the Swiss federal agency for meteorology using local regressions with an elevation model to better account for local topography and complex local climatic phenomena. Climatic layers are provided for individual years, 1981–2010 baseline period and future periods 2020–2049, 2045–2074, and 2070–209. Future layers incorporate three regional/global circulation models and three representative concentration pathways. We compare our predictions with values observed at independent weather stations and show that errors are minimal in comparison to the original dataset at 1 km resolution, and that the dataset is more accurate than available climatic global datasets at 30’ resolution, especially at high elevation. CHclim25 improves the temporal and spatial accuracy of climatic data available for Switzerland and enables new studies at very high resolution in ecology and environmental sciences.