This study examined smallholder farmers’ perceptions of the effects of climate change-induced rainfall variability on cassava production in selected local government areas (LGAs) of Imo State. A multistage sampling procedure was used, comprising the purposive selection of LGAs and agricultural communities and the random selection of farmers. Cochran’s formula was applied to determine a sample of 60 farmers, and data were collected using questionnaires. Descriptive statistics, correlation analysis, the Kruskal–Wallis test, probit regression, and principal component analysis were employed. The Kruskal–Wallis test (p = 0.042) indicated significant differences in perceived rainfall effects across the three LGAs. The post hoc analysis identified a significant difference only between Ngor Okpala and Ohaji/Egbema. Principal component analysis identified three dominant dimensions of the perceived effects of rainfall variability on cassava production: environmental and accessibility challenges, agro-climatic disturbances, and income–cost pressures. Inorganic fertiliser application was the most commonly adopted strategy, practised by 68% of respondents, with a weighted mean score of 2.71. Probit regression showed that gender significantly influenced tree planting as an adaptation practice, whereas farming experience significantly influenced diversification into other income sources. The study recommends improved access to irrigation facilities and markets, together with support for income diversification, to strengthen farmers’ capacity to manage rainfall-related production risks.