Many parts of China have experienced frequent and severe droughts over the past century, particularly southwestern China. These severe droughts had substantial ecological and socioeconomic impacts. Cognition and awareness of water deficit is important to understand the supply-demand situation, ensure rational utilization of water resources, and minimize the adverse impacts of drought. This study analyzed the spatiotemporal variation of water deficit rates during the rice growing seasons in southwestern China over a period from 1960 to 2013. The Penman-Monteith model was used to estimate the reference evapotranspiration of rice during the growing seasons and a simple approximation following the method developed by the USDA Soil Conservation Service was used to compute the effective precipitation. Pearson's correlation coefficients were then used to evaluate the linear relationships between water deficits and oscillation factors, although the model data frequently underestimated non-linear information, and synthetic analyses were used to further reveal the characteristics of water deficit anomalies in response to fluctuations in the North Atlantic Oscillation (NAO) and El Niño Southern Oscillation. Furthermore, we analyzed the relationships between spatial patterns of rice water deficits and geographical environments and attempted to identify the most important explanatory drivers for the spatial distribution of water deficits in southwestern China. The results showed that the amount of rice water deficiency was negative for the growing seasons in the study area during 1960-2013, which means that water surpluses persisted in aggregates. The spatial distribution of rice water deficiency was affected by climatic and geographic factors. Rice water deficiency presented a clear pattern that was high in the eastern hilly region and low in the Yunnan-Guizhou Plateau. Water deficit and surplus in some regions displayed a "one stripe with two centers" pattern, e.g., eastern hilly region, east Sichuan, and eastern Guizhou Plateau comprised one saddle-shaped deficit region. Ganzi-Xiaojin, located northeast of the Hengduan Mountains, and Yuanjiang-Meizi, in the Red River Valley of the Yunnan Province, displayed two deficit regions. The southwestern margin of the Yunnan-Guizhou Plateau was one surplus region, whereas Laifeng-Youyang in the Wushan Mountains and Leshan-Ya'an in the low mountain-hill area around the western Sichuan basin comprised two surplus regions. Spatial trends of rice water deficiency showed "drying over the whole area and wetting in parts" patterns in southwestern China during 1960-2013. Water deficiency had an increasing trend in southern parts of the Ganzi-Qinzhou line, whereas data showed alternate increasing and decreasing trends in northern parts of the Ganzi-Qinzhou line. The synthetic analysis revealed that anomalies for rice water deficiencies were induced by remote forcing from the tropical Pacific and North Atlantic Oceans. During the positive phase of the NAO, other than a few hilly areas in the Guangxi Province, the land became much drier and rice water deficiency increased significantly during the growing season. During El Niño years, rice water deficiency showed obvious spatial differences whereby decreasing trends were detected in eastern hilly areas and increasing trends were detected in other regions. Together, these findings highlight that increases of rice water deficiency during growing seasons can aggravate the discrepancies between water supply and demand and increase agricultural fragmentation in southwestern China.