ABSTRACT. - Study of rainfall periods calculated over three months intervals in the Somes Plateau. The precipitation periods of the Someş Plateau were determined using the weighted anomaly standardized precipitation (WASP). We processed and analyzed data from the period between 1970-2008 from two meteorological stations and nine rainfall stations. WASP values were calculated for intervals of three months (a season). The frequency analysis was done on three domains of the precipitation periods (rainy, normal and dry). The rainfall risk characterization was studied on three groups: risk by excess, risk by deficiency and free of risk. By analyzing the resulting rainfall periods the normally domains have the predominant share followed by the dry and wet domains. The frequency analyses of the groups with risk and without risk indicate a net predominance of situations without rainfall risk. In the spatial distribution of exceeding rainfall periods appear some contrasts, determined by the position of stations and posts regarding the prevailing western air masses advections.
Key words: rainfall periods, classes, fields, rain-risk groups