Variability of the lowest monthly precipitation sums in the Silesian and Żywiec Beskids

The study was based on monthly precipitation sums from at eight precipitation stations in the Silesian and Żywiec Beskids, covering the period 1951–2022. The data were obtained from the Institute of Meteorology and Water Management – National Research Institute. The frequency and year-to-year variability of the precipitation sums, as well as seasonal variability, based on Colwell’s predictability index (P) and its components: constancy (C) and seasonality (M). The results show that low precipitation occurred in all months of the year, with the highest frequency in October, and sporadically recorded in May, June, and July. The majority of the lowest monthly precipitation sums ranged between 30–50 mm, although in some, values exceeded 65 mm. Dry months were recorded in the study period of 1951–2022, notably October 1951, when precipitation sums at the stations did not exceed 3.5 mm, and November 2011, when they did not exceed 1.5 mm. Compared to the long-term average, these precipitation sums accounted for less than 5%. No significant trend was observed in the lowest monthly precipitation sums, though short-term fluctuations were present. Analysis of Colwell’s indices showed that the predictability of the lowest annual precipitation sums was below average, at approximately 0.40 across the analysed stations. Seasonality (M) was the dominant component of predictability, accounting for an average of 71% of the total predictability. The research findings may contribute to the understanding of the variability and forecasting of extreme meteorological droughts in the Polish Carpathians, particularly with implications for agriculture and forestry.