The increasing demand for clean and sustainable energy has accelerated the deployment of grid-connected solar photovoltaic systems across residential, commercial, and utility-scale applications. While solar photovoltaic technology offers significant environmental and economic benefits, its performance is highly dependent on environmental conditions such as solar irradiance, temperature, and atmospheric factors. Variations in these parameters influence power output, system efficiency, and grid stability. This study presents a comprehensive performance analysis of grid-connected solar photovoltaic systems operating under variable environmental conditions. The research examines the impact of irradiance fluctuations, temperature variation, and seasonal changes on power generation efficiency, voltage stability, and energy yield. Mathematical modeling and empirical performance assessment are employed to evaluate system behavior. The findings highlight the critical role of environmental factors in photovoltaic performance and emphasize the need for adaptive control strategies to enhance system reliability and efficiency.