The stability of slopes under rainfall conditions depends on the rainfall intensity, permeability, and soil water characteristics. The soil water characteristic curve (SWCC) connects soil suction to the soil water content. The SWCCs estimated using drying and wetting the soil samples are not identical because of the effect of hysteresis. The stability analysis of the slopes under drying and wetting cycles is not fully understood yet. Hence, in this study, the influence of drying and wetting SWCC on slope stability is examined and presented for a real case study. A massive slope failure was reported on the 9th of August 2018 due to severe rainfall at Idukki, Kerala. The influence of drying and wetting SWCC on the factor of safety of the Idukki slope is illustrated. An analytical study has been developed to examine the stability of the Idukki slope. Furthermore, the slope is analyzed for various rainfall intensities. Additionally, the critical failure surfaces at the time of failure for both drying and wetting SWCCs are presented. The findings demonstrated that wetting SWCC and rainfall intensity play a significant role in the stability analysis of slopes under rainfall conditions. Further, a significant shift in the position of the critical slip surface is observed for both drying and wetting SWCCs in unsaturated conditions. The wetting SWCC should be given consideration than drying SWCC in the stability analysis of rainfall-induced slope failures.