## 3 Results and Discussion
### Evaluation and Trends  
The variability in absolute values of the analyzed parameters for 49 cities is shown on violin plots representing the distribution. The violin plots depict the probability density of the data at different values, showing the shape of the distribution. The period for the climate horizon 2010 was averaged for 2006-2015. Predictions for future horizons were calculated using a similar approach, presenting the average value for all locations with violin plots representing the distribution of the selected quartiles. The time spans for the predictions were as follows: the average for 2026-2035 represented the horizon for 2030, and the average for 2046-2055 represented the horizon for 2050. The ensemble models employed in this study were statistically corrected using a quantile mapping approach, with observations from weather stations recorded between 2006 and 2015. Significant trends related to changes over the coming decades were observed for most of the analyzed parameters. In the case of the average annual temperature, the range of variation in the observations, the results of the models, and the average values for 2010 are in good agreement (Figure 9). In both scenarios, an increase in the annual average temperature is observed. In the 2030 horizon, the projected values are similar and equal to 9.5 \({}^{\circ}\)C on average. Further growth is predicted for 2050, from an average of 10.0  
An increase in the number of hot days is predicted as a direct consequence of the maximum daily temperature increase in all of Central Europe, shown, e.g., in [52; 53; 54] or in the recent work of [55]. However, these scenarios show different dynamics (Figure 9). In RCP4.5, there is a significant increase from 11.5 to 13.9 days on average in the 2030 horizon and stabilization with a slight upward trend in the 2050 horizon (14.8 days on average). In RCP8.5, the growth in the 2030 horizon is smaller (13.4 days on average), while in the 2050 horizon, it shows much larger values--16.4 days on average. The number of frost days in the current climate conditions (horizon 2010) for the observation and model is similar. The differences between RCP scenarios represented by the violin plot range do not exceed one day (Figure 9). The average observation for all cities is 98 days compared to 97 days for the modeled value. The projected trends in both scenarios are very similar for the 2030 horizon. They are expected to decrease to 90 days in RCP4.5 and 89 days in RCP8.5. A more significant disparity between the trends is predicted in the next time horizon (2050). In the RCP4.5 scenario, a further decrease is predicted, with an average of 83 days. In the RCP8.5 scenario, a more significant decrease is predicted, reaching 74 days (Figure 9). In terms of the number of cold days, the range of variability in the observations and the results of the models' ensemble in the current climate conditions (2010) are similar (Figure 9). The average value for the models' ensemble is 30.5 days compared to the average value of 31 days for the observations. In the first time horizon, until 2030, a substantial decrease is predicted in both emission scenarios. The decrease in the RCP4.5 scenario is more dynamic (falling to 27 days) compared to 28 days in the RCP8.5 scenario. In the 2050 horizon, a further decrease is predicted in both scenarios, down to 22.4 days. The average trend line in scenario RCP8.5 for all cities suggests more dynamic droop than in scenario RCP4.5. Figure 9: Variability in (**a**) annual average temperature, (**b**) the number of hot days (Tmax > 30 \({}^{\circ}\)C), (**c**) the number of frost days (Tmin < 0 \({}^{\circ}\)C), (**d**) and number of cold days (Tmax < 0 \({}^{\circ}\)C) for 49 cities in Poland based on the results of statistical correction of the EURO-CORDEX model ensemble for the 2010 horizon, the 2030 horizon, the 2050 horizon, and the observations from weather stations for the 2010 horizon.