<p>The sun plays a crucial role in Earth's climate, where even minor fluctuations in solar radiation can significantly impacts regional climate conditions. Understanding the relationship between solar radiation and regional climate patterns is essential for improving climate modelling and forecasting accuracy. However, despite its importance, the interaction of solar radiation with tropical systems remains inadequately investigated. This study explores the relationship between solar radiation and climate variability in northern Peninsular Malaysia, a key agricultural zone. The Vector Autoregressive (VAR) model was employed to analyze the relationship between solar radiation and the De Martonne Aridity (DM) Index, which serves as a proxy for climate variability. The findings show that the region experiences dry conditions from December to January, potentially extending from March to May, while the wettest season occurs between September and November. The Modified Mann–Kendall (MMK) analysis reveals a significant increasing trend in both DM and solar radiation across most assessed stations, indicating a warming and more humid climate in this region. Additionally, the Impulsive Response Function (IRF) analysis suggests a pronounced response of DM to solar radiation shocks, with long-term effects persisting for over two decades. Furthermore, variations in solar radiation account for approximately 5% of surface temperature variability. These findings highlight the direct and long-term influence of solar radiation on the climate system in northern Peninsular Malaysia. They underscore the role of solar radiation in shaping regional climate variability, with implications for solar radiation management as a potential climate mitigation strategy.</p>