A Review of Solar Panel Efficiency in Different Weather Condition

Abstract

Solar photovoltaic (PV) systems are now widely recognized as an important response to the growing demand for cleaner energy. Yet their performance is never constant. Day by day, and sometimes even hour by hour, output changes because weather conditions directly affect sunlight levels, surface temperature of the modules, and even the cleanliness of the panels. In this review, I bring together findings from earlier studies as well as simple field observations to show how efficiency shifts under three common situations: clear skies, cloudy weather, and periods of rain. On bright sunny days, panels naturally produce the most power, but very high heat can cause a gradual drop in efficiency-often around 0.3 to 0.5% for every degree Celsius above the test standard. Under cloudy skies the output usually falls, sometimes by 20% and in heavier conditions even up to 60%. Rainy days cut irradiance as well, though rainwater also cools the panels and helps clean away dust, which may partly balance the loss. These patterns suggest that designers and users should not only think about maximum output but also about local weather variability. Choosing the right tilt, keeping modules clean, and combining systems with storage can improve stability over the long term.