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This study focuses on demonstrating the multiannual patterns of cyclical fluctuations of monthly and annual precipitation in the Polish Carpathian Mountains and their foreland. The study is based on secular series of precipitation totals from 18 meteorological stations for the 138-year period from 1881 to 2018. Use is made of Fourier analysis (FFT) and wavelet transform nonlinear estimation. The study has found a 35-year Bruckner cycle in annual precipitation across the area. The number of days during the year with the types of cyclonic circulation that lead to extremely high precipitation, i.e. with the northerly and north-easterly (Nc + NEc) types and a cyclonic trough (Bc), is not clearly correlated with the 35-year harmonic variability derived from annual precipitation totals. However, the Fourier transform demonstrates a local maximum at T = 35 years. A harmonic 6-month cycle has been discovered as the only harmonic cycle in monthly precipitation. Its stability over the 138-year timespan is investigated.

Extreme climatic phenomena include prolonged heavy precipitation as well as long-lasting absence thereof. They are a consequence of weather anomalies and have many dangerous effects such as floods and droughts. This study aims to characterise the annual and long-term variability of the highest (Pmax) and lowest (Pmin) monthly precipitation totals and their relationship with atmospheric circulation. To achieve the above, use is made of 14 secular series (1881–2018) of precipitation from the Polish Carpathians and the calendar of circulation types over southern Poland prepared by T. Niedźwiedź (1981, 2019). On account of the variation in their relief, the Polish Carpathians are an area with a very great temporal and spatial variability in precipitation, ranging from complete absence to 500 mm per month. Pmax demonstrates a more noticeable annual frequency pattern, with a predominance in summer months, while Pmin shows smaller variations in individual months. Both Pmax and Pmin are characterised by irregular fluctuations in precipitation totals, with no statistically significant trend in their changes, which reflects the absence of a trend as regards overall precipitation volumes in this area. The study confirms an influence of the direction of air mass advection and (anti)cyclonicity of flow on Pmax and Pmin.

The current climate warming phenomenon manifests itself with the occurrence of, among other characteristics, extremely hot months and seasons. Examples include the heat waves of April and May 2018 and of June 2019, which swept through large areas of Europe with considerable damage to nature and the economy. The study looks at thermal anomalies of this kind using average monthly air temperature records from 210 weather stations collected over the period 1951–2018. For the purpose of the study an anomaly was defined as a deviation of the average monthly temperature from the long-term average by at least two standard deviations. An anomaly was considered large-area if it occurred simultaneously at 20 or more stations, which corresponded to about one-tenth of the continent. The study found that positive large-area anomalies were increasingly frequent, some being recorded at 80 stations, and that no cool large-area anomalies were recorded after 2010. Large-area thermal anomalies of both types were the most frequent overall in Central Europe.

Extreme thermal conditions appear to occupy an important place among research subjects at a time of climate warming. This study investigates the frequency, duration and spatial extent of thermally anomalous winters in Europe during the 60 years between 1951 and 2010. Exceptionally cold winters (ECWs) and exceptionally mild winters (EMWs) were identified using the statistical criterion of plus/minus two standard deviations from the long-term winter temperature (January–December) recorded at 60 weather stations. It was demonstrated that ECWs have occurred more frequently and covered larger territories than EMWs and that they may occur anywhere in Europe, while EMWs were limited to its southern and western parts. ECWs are characterised by greater absolute temperature anomalies, as anomalies greater than |6.0 °C| account for 35 % of ECWs, but only for 8 % of EMWs. The greatest anomalies are found in the east of the continent. The largest territory affected by an ECW included 24 stations in 1962/1963, while the equivalent among the EMWs included 11 stations in 2006/2007. The study also confirmed an expected trend whereby ECWs diminished in frequency in favour of EMWs in the second half of the 60-year study period.

Based on the monthly precipitation series from 16 sites (in the Polish Carpathian Mountains), of 132 years’ length, a relatively precise scatterplot of correlation coefficients between sites versus distance between sites is obtained. The “rains” of Gaussian shape, in the spatial sense, are a good model, which produces a scatterplot very closely resembling the observed one. The essential parameter of the model is the area covered by the modeled rains, which results to be of order 30–50 km, though with about a twice lower value for the N-S direction.

In Europe, the current climate warming manifests itself with an increasing frequency of anomalously warm months (AWMs) and a declining frequency of anomalously cold months (ACMs). For the purpose of the study the authors define thermally anomalous months as months with the average air temperature at least two standard deviations higher or lower (AWM: t ≥ tav. + 2SD, ACM: t≤tav. - 2SD) than the long-term average (1951-2010). The aim of the study is to investigate the frequency of such monthly anomalies in southern Europe (approximately south of 45°N) in the Mediterranean and in Asia Minor (based on records from 80 weather stations), the change in such frequency over the 60-year study period, as well as the location of the anomalies and their coverage area. The number of ACMs and AWMs showed significant variations over the 60-year period.

The paper addresses the frequency, amount and geographic coverage of anomalously heavy precipitation in southern Poland in relation to atmospheric circulation at the monthly and seasonal scales between 1881 and 2010. The Carpathian Mountains and their foreland were selected for the study as an area known for its high precipitation totals and frequent precipitation-triggered natural disasters, such as floods and landslides. Records from 18 stations were used to identify anomalously heavy precipitation (AHP) defined for the purposes of the study, as the top quartile (Q75 %) plus 1.5 times the interquartile gap (H) of the precipitation total (P ≥ Q75 % + 1.5H). The study found that most cases of AHP were recorded at one single station each. This suggests that, in addition, to the influence of circulation, local factors also play a major role in the formation of particularly heavy precipitation. The greatest absolute anomalously high precipitation totals were recorded in two disparate parts of the study area: (i) its western part exposed to wet air masses from over the Atlantic Ocean brought in by the dominant western circulation in the temperate zone and (ii) elevated parts of its south-eastern part. Two months with AHP (AHP months) occurred over the entire area (18 stations) in May 1940 and 2010. The latter case had both the greatest absolute totals (over 500 mm) and relative totals defined as their ratio to the long-term average (500 %), and it triggered a catastrophic flood in the Upper Vistula basin.

Investigation of extreme thermal conditions is important from the perspective of global warming. Therefore, this study has been undertaken in order to determine the frequency, timing and spatial extent of extremely cold months in winter time at 60 weather stations across Europe over a sixty-year period from 1951 to 2010. Extremely cold months (ECMs) are defined as months in which the average air temperature is lower than the corresponding multi-annual average by at least 2 standard deviations. Half of all the ECMs occurred in the years 1951–1970 (33 out of 67). The lowest number of ECMs was recorded in the decade 1991–2000, but since the beginning of the 21st century, their density and territorial extent has started to increase again. The extremely cold months with ECMs of the greatest spatial extent, covering at least one third of the stations (over 20 stations), included: February 1954 (22), February 1956 (36), January 1963 (25), and January 1987 (23 stations).