The purpose of the research was to characterize the variability of relative air humidity in the growing season in the vicinity of Bydgoszcz in the years 1985-2010. The study was based on measurements taken from a representative meteorological station located within the Airport Bydgoszcz-Szwederowo. Standardized air humidity measurements were carried out in a thermometer shelter, by Assmann psychrometer at the height of 2 m above the ground, on the plateau, about 3.5 km from the city center. The study investigated the nature and scope of changes in mean relative humidity by calculating selected elements of descriptive statistics. Based on the linear function of Regression analysis we determined direction of changes and specified the ratio with time of analyzed indicator. The average relative air humidity in the Bydgoszcz vicinity, especially in the spring and summer months, was characterized by a large temporal variability, appropriate to moderate and transitional climate in Poland. The variability of the analyzed indicator in multi-year period 1985-2010 was not statistically confirmed. It was found a temporary widening of variation in 5 of the 7 examined cases in period 1998-2010 compared to the previous period 1985-1997. ...
