Within this paper, changes of the runoff coefficient for the Slani potok catchment area during 2014 is analysed. Slani potok catchment area is placed in Vinodol valley (Primorsko-goranska County). Based on the available meteorological and hydrological data, total rainfall volume, as well as the runoff rainfall volume were calculated in order to determine the runoff coefficient for ten significant rain events during 2014. The results indicate, as expected, that the runoff coefficient values are significantly lower in the summer period of the year in comparison to the winter period. In the period from May 28 to September 1, value of runoff coefficient has span from 0,09 to 0,18, while in the rest of the year is between 0,17 and 0,31. Average annual coefficient value is 0,19. The processes of evaporation as well as the spring growth of vegetation, have significant impact on the rainfall runoff conditions on the catchment area of the Slani potok. Continuous measurements of the meteorological (Δt = 10 min) and hydrological (Δt = 2 min) parameters with small measurement time step is crucial for this type of the rainfall-runoff analysis, considering the torrential flow character and short time or concentration for the researched catchment area. The results of the research showed that this kind of research measurement methodology has a potential of implementation on the similar small catchment areas characterized by torrential flow across the Republic of Croatia in order to conduct more detailed and accurate research measurement and determining of runoff coefficient.