Climate and water cycle determine the living conditions on Earth and affect, for example, agriculture, forestry, water management and the availability of drinking water. Climate and precipitation – one of the main components of the water cycle - within a region depend on geographical position, topography and prevailing land use; they often show a pronounced variability in time and space, even over small distances. It is also often observed that the distribution of extremes differs considerably from the one for average values, e.g. patterns of heavy precipitation differ from the patterns of annual precipitation sums. Studying the past, present and future behaviour of climate and water cycle on regional scales is essential for climate adaptation issues, but also for a better understanding of this multi-component, multi-scale system, and numerical models are a suitable tool for these purposes. Our working group is engaged in the modelling, the analysis and the interpretation of the intimately connected topics water and climate on the regional scale with high spatial resolution.