Aerosol optical parameters obtained from sky radiometer instrument are important not only for studying aerosol effects on climate change, but also for validating several results obtained from satellite retrievals and numerical simulations. However, the greatest challenge is to separate cloud-affected and cloud free data from data measured by sky radiometer. In this study, we present an algorithm to separate such cloud-affected and cloud free data. The proposed algorithm is comprehensively tested with observational data. The algorithm consists three tests: (i) test with global irradiance data, (ii) spectral variability test, and (iii) statistical analyses test. Though the test with the global irradiance data is the most powerful test, our study shows that it has some limitations, which can