The Daoura watershed is considered an arid environment in southeastern Morocco. This situation exposes it to significant spatial-temporal rainfall contrasts, which have a detrimental effect on the water resources of its oasian territory. The primary goal of this study is to guarantee the coverage, continuity, and dependability of our data by homogenizing rainfall data from 13 stations between 1957 and 2018. Patterns of rainfall variability throughout the research area have been identified using principal component analysis with a Varimax-type rotation, and the spatiotemporal variability of rainfall has been examined using wavelet transform analysis. In this context, an analysis of the time series of rainfall data is necessary to understand the mechanisms of frequent climate in the Daoura watershed. It is based on the study of regional and temporal (annual and inter-annual) rainfall variability. The spatial-temporal rainfall data were divided into three homogenous sub-regions using principal component analysis with Varimax-type rotation: (1) High Atlas; (2) Errachidia Cretaceous Basin and South Atlasic; and 3) Tafilalet anti-Atlasic and alluvial plain. The results obtained revealed significant power durations at frequencies that are generally discontinuous and differ from one station to another. In the study area, the most common frequency is one to two years and the significant fluctuation can last up to eleven years. It was observed between 1960 and 1980 on almost all of the Daoura, while the majority of stations have identified frequencies of 16 to 32 years extending from 1970 to 2018. The fluctuation pattern appears to be intermittent in some places and persistent in others, lasting from two to four years.