The infiltration precipitation into the soil is the primary cause of rainfall-induced slope failures. Rainwater infiltration into the soil primarily depends on soil water retention. Soil suction at a given soil moisture can be evaluated by a soil water characteristic curve (SWCC). SWCCs obtained by drying and wetting the soil specimen methods are not identical due to the effect of hysteresis. The response of slopes to drying and wetting cycles due to rainwater infiltration is yet to be known completely. Hence, the key objective of this study is to understand the behavior of the Marappalam slope to drying and wetting cycles due to rainwater infiltration. A massive Marappalam slope failure on the 10th of November 2009 is reported due to heavy rainfall in Tamilnadu. The finite element program SEEP/W has been used to estimate the changes in the factor of safety caused by hysteretic SWCC on this slope. It is followed by performing the probabilistic analysis to compute the failure probability using Monte Carlo Simulations for the Marappalam slope under hysteretic cycles. The findings revealed that the factor of safety of this slope changes significantly under rainfall conditions and hysteretic cycles. The results demonstrated that hysteretic SWCC in the soil plays a primary role in rainfall-triggered slope failures. The probability of failure is found to be sensitive to drying and wetting cycles. This case study signifies the importance of considering wetting SWCC in the analysis of rainfall-triggered slope failures as it depicts the real-field conditions. The study emphasizes the significance of taking the variability of shear strength parameters into account. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.