Monsoonal Dynamics and Rainfall Extremes in Salem, Tamil Nadu, India: Insights from a Climate Variability Perspective

Abstract

India, characterised by its diverse climatic zones and reliance on monsoonal rainfall, is particularly vulnerable to climate change. Over recent decades, the country has experienced significant alterations in rainfall patterns, including shifts in monsoon onset, intensity, and distribution, leading to increased frequency of extreme weather events such as floods and droughts. The study aimed to gain insights related to monsoonal dynamics and rainfall extremes in Salem. A 40-year analysis (1984–2024) of rainfall in Salem, Tamil Nadu, India, reveals a strong monsoonal influence and marked inter-annual variability. Annual rainfall totals peaked at approximately 1250 mm (2022) and dipped as low as ~420 mm (2014), reflecting extreme wet and dry years. While no definitive long-term trend is evident, recent decades show an increased frequency of extremes. Monthly data highlight October–November (Northeast Monsoon) as the wettest period (October ≈150 mm), while January–February remains the driest (~10–15 mm). Seasonal analysis shows that the Southwest Monsoon (June–September) and Northeast Monsoon (October–December) contribute ~35% and ~33% of the annual total, respectively, with summer and winter contributing ~22% and ~10%. These fluctuations carry major implications for watershed management, underscoring the need for high storage during wet years and resilient planning during droughts. The observed variability and frequency of extreme events are consistent with climate change projections, indicating intensified monsoon rains and more prolonged dry spells. Understanding these patterns is therefore crucial for sustainable water resource planning and climate adaptation in the region. The evidence presented in this study provides a scientific foundation for climate-informed planning, urging policymakers, water managers, and communities to act proactively, ensuring water security and ecological stability for the coming generations.