Understanding the shifts in rainfall persistence under a warming climate is crucial for managing water resources in regions reliant on the monsoon. This study explores the behavior of wet and dry spells utilizing daily precipitation and temperature data from the India Meteorological Department (1951–2020), along with projections from a mean ensemble of five CMIP6 models covering 2020–2100. The analysis focused on the monsoon season (June–September) under two emissions scenarios: SSP2-4.5 (moderate) and SSP5-8.5 (high). Trend analyses using the Mann–Kendall and Sen’s slope tests reveal no significant changes in annual rainfall totals. However, both minimum and maximum temperatures exhibit pronounced and statistically significant upward trends under all scenarios, with minimum temperatures increasing at a faster rate than maximum temperatures. Spell-based indices offer more distinct patterns than annual precipitation figures. The longest dry spells (CDD) shrink from around nine days at the start of the projection period to nearly zero by century’s end, indicating that long intra-monsoon dry intervals may become rare. In contrast, the longest wet spells (CWD) show a steady rise, often surpassing 120 days under SSP5 by the late century, suggesting more continuous wet-season conditions. Mean spell lengths reinforce this pattern, with wet spells extending to 15–20 days in some decades, while dry spells contract from historical durations of 10–15 days to about 5–8 days. Distributional analysis reveals an increased likelihood of exceptionally long wet spells and a significant decline in extreme dry spell occurrences. The correlations between temperature and spell metrics further highlight the impact of warming on rainfall persistence. Wet spells show strong positive associations with both Tmin and Tmax (r > 0.89), whereas dry spells are significantly negatively correlated (r ≈ −0.80). The results of present study signals for a future defined by prolonged wet monsoon phases with increasing risk of flooding even with insignificant changes in total annual rainfall.