The current manuscript applies a previously developed and validated evaporative cooling theoretical model to a wide range of scenarios aiming to infer the actual effectiveness of evaporative cooling on building roofs as a way to reduce the excessive thermal load. The presented analysis is divided in three main sections, one of parametric nature, which considers standard or idealized variation for wind speed, solar irradiation, ambient temperature and relative humidity, one using real weather data and the third one that based on TMY data from several locations around the world, which are employed to evaluate the applicability of evaporative cooling for different climates. The parametric analyses indicate that air relative humidity and temperature variations present, arguably, the strongest influence on the performance of the evaporative cooling compared to other roof heat gain reduction methods. The global analysis indicates that arid climates such as BSk and BWh, from the Koppen classification, are more likely to display encouraging results with respect to the evaporative cooling whereas in humid equatorial climates the benefits are modest.