Western Ghat (WG) region with mountainous terrain runs parallel to the western coast of India from Kerala to Gujarat is one of the highest rainfall recording regions in the world. Being one of the hottest hotspots of biodiversity and birth place of major river systems, the WG plays a crucial role in sustaining livelihoods across peninsular India. Hence it is essential to analyse the nature of rainfall variability and trend. Researchers commonly employ the Mann–Kendall test along with Sen’s slope estimator to analyze and quantify trends, with recent adoption of innovative trend analysis methods for data exhibiting serial correlation. Notably, factors such as elevation, slope, and width of the WG significantly influence rainfall patterns, while global climatic phenomena i.e. sea surface temperature (SST) exert a pronounced impact on its central and northern sectors. It has been observed that elevation, slope and width of the WG has profound influence on the amount of rainfall and also global climatic phenomenon i.e. SST has more impact on Central and Northern part of WG. Although the El Niño Southern Oscillation (ENSO) has a relatively minor direct impact on overall monsoonal rainfall, it does influence the onset and withdrawal of the monsoon within the region. Long-term analysis reveals a decreasing rainfall trend in the southern part of the WG, contrasting with an increasing trend observed predominantly in its central and northern region. Similar trends manifest in Kodagu district, characterized by decreasing annual rainfall alongside a rise in extreme events, underscoring the necessity for an expanded observational network within the WG to comprehensively address the impacts of shifting rainfall patterns and climate change.