The study characterises the variability of total solar radiation intensity in Krakow from 2012 to 2021. The aim of the study was to demonstrate the influence of cloud cover (cloudiness and cloud genera) and air pollution on the solar energy flux reaching the Earth’s surface. Data were collected from the Scientific Station of the Department of Climatology of the Institute of Geography and Spatial Management of the Jagiellonian University, utilising a unique 10-year period due to gaps in instrument operation in 2011. The analyses confirmed that astronomical factors primarily determine the cyclic variability of solar radiation throughout the year and day. The impact of the cloud structure in weakening and enhancing the magnitude of the energy flux was demonstrated. It was found that under cloudless weather conditions, total irradiance is reduced (by up to 20%) when the air is polluted by PM2.5 and NO2.
