As a consequence of the global warming we assist in the last decades at the intensification of extreme weather or hydrological events, such as droughts, hail storm or flash floods. This paper examines some spatial and temporal manifestations of maximum intensity of rainfall in the warm season, in Northwestern Romania. Diurnal variation, duration, and intensity of the maximum rainfall intensity as well as the return periods of the absolute values, the statistical probability of recording higher values and trends have been detected. Annual maximum intensity values of precipitation recorded in 14 weather stations over a period of 35 years (1975-2009) have been considered. HYFRAN and MAKESENS software have been employed for statistical analysis. The data sets were tested to check if they were identical and independent distributed at the 95% of significance level. The main findings are: maximum intensity extreme values varies between 5.0 and 10.) mm/min; the highest frequency of rainfa ll maximum intensity is specitic in the afternoon and in the evening; the frequency of events with certain maximum intensity duration dramatically decreases from 45 .5 % for 1 minute period to 0.6 % in the case of those events lasting more than 8 minute; the return periods of absolute maximum intensities are generally ranging between 30 and 80 years, wh,jJe the absolute minimum intensities have the return periods between 1.002 and 1.06 years; almost 80 % of the locations indicated increasing trends in the maximum intensity of rainfall. All these findings are very important for modeling the flash flood parameters.