With global temperatures steadily rising, understanding the impacts of warming on regional climates has become crucial, particularly for countries like India, where climate sensitivity has significant socio-economic implications. This study assesses the trends and spatial distribution of summer days across India under different warming targets (1.5 °C, 2 °C, 2.5 °C, 3 °C, 3.5 °C, 4 °C, 4.5 °C, and 5 °C) and emission scenarios (RCP4.5 and RCP8.5). A Multi-Model Ensemble (MME) approach, combining five best-performing CORDEX-SA experiments, was utilized to analyze projected summer days in India. Non-parametric trend analysis techniques—such as the Mann–Kendall test, Modified Mann–Kendall, Sen’s Slope estimator, and Pettitt test—were used to investigate temporal patterns, and Reliability Ensemble Averaging (REA) was applied for uncertainty analysis to ensure robust projections. The results indicate that summer days are expected to increase significantly across India under both RCP scenarios, with the highest increases projected for northeastern regions and north-central regions of India. This study underscores the pressing need for region-specific adaptation strategies to manage extended periods of extreme temperatures and safeguard public health, agriculture, and socio-economic stability.