The work investigates precipitation variability in the Alps and their surroundings based on 157 instrumental series of monthly total precipitation. A discussion of the initial homogenising procedure illustrates its advantages and risks. A comparison of the homogenised series with the original series clearly shows the necessity to homogenise. Each of the original series had breaks and the mean of all series was systematically biased by non-climatic noise. The relatively high spatial resolution of the data enabled a regionalisation within the study area of 680,000 km2 into sub-regions based on principal component analysis of the monthly series. Thus the series will be grouped, the mean regional precipitation will be calculated and analysed for trend and the results will be presented.