Dynamic impact of temperature, humidity, and dew point on photovoltaic power output: An empirical analysis of real-case hourly data

As Europe intensifies its efforts to reduce greenhouse gas emissions, optimizing renewable energy sources, particularly solar power, has become essential. This study examines the effects of ambient temperature, humidity, and dew point on the electricity output of a photovoltaic (PV) system using real-time operational data from a 1.27 MWp installation in Cyprus during 2021. We analyze the plant-specific performance through regression analysis. To enhance generalizability across different climatic regions and system sizes, PV output is normalized against the system's theoretical production potential. This is expressed in percentage points (pp) of installed capacity. The results demonstrate that ambient temperature has a strong positive linear relationship with electricity generation, yielding approximately 16 kWh per 1 °C increase, equivalent to 1.26 pp of the system's potential. Conversely, humidity exhibits a negative impact, reducing output by 0.086 pp for each 1 pp increase in relative humidity. The dew point shows a positive effect of 1.07 pp per °C when used as the sole explanatory variable. When analyzed alongside ambient temperature, the dew point follows an inverted U-shaped relationship with a turning point at 8 °C. Month-specific analysis reveals that temperature effects vary seasonally, with the largest marginal impacts occurring during winter months (February and March) and smaller marginal effects during summer months. These findings provide practical insights for optimizing PV system performance and inform renewable energy planning strategies in Mediterranean climates. The normalization approach enables cross-regional performance comparisons and supports evidence-based decision-making for future solar installations.