Precipitation variability is a slow, chronic change in precipitation fluctuations that does not include individual extreme events. It primarily affects the availability of water and water levels, thus influencing various water users (e.g., water management and ecosystems) as well as all economic sectors that depend on sufficient quantities of water (e.g., tourism, inland navigation and production).
The variability of precipitation generally has no direct impact on buildings, except in the case of acute hazards such as flooding. However, long-term changes in water availability can affect the quality of life and living conditions of residents.
The risk assessment is based on the annual precipitation amounts, with the standard deviation of the annual precipitation being calculated. If this is high, it means that the rainfall amounts fluctuate significantly from year to year.