The thesis addresses the impact of spatial averaging of actual winds on the circulation in the Gulf of Trieste. The given wind fields were averaged from resolution of 150 x 150 m over four- and ninefold larger areas, the latter in two ways, in each hour of the seventy-two hour simulation period. Hydrodynamic simulations were performed with the PCFLOW3D model. The results were mapped at the depths of 0.5 m and 10.5 m. Due to small differences between the currents we also analysed the results numerically. In both layers we observed significant differences in currents only near the coastline, at the open boundary and closer to the seabed, where the boundary conditions have greater impact, while elsewhere the differences were minimal. Any of the examined wind averaging techniques may be used for further modelling, as the error of the space averaging does not exceed the inaccuracy of the PCFLOW3D model and of the input data.