Two models for solar radiation attenuation in the atmosphere are presented. The novelty consists in using fuzzy logic algorithms for evaluating atmospheric transmittances associated to the main attenuators: Rayleigh scattering, aerosol extinction, ozone, water vapor and trace gas absorption. The first model encompasses self-dependent fuzzy modeling of each characteristic transmittance, while the second is a proper fuzzy logic model for beam and diffuse atmospheric transmittances. The assembly of our results leads to the conclusion that developing parametric models along the ways of fuzzy logic is a viable alternative to classical parameterization. Due to the heuristic nature of the fuzzy model input-output map, it leads to more flexibility in adapting to local meteo-climatic conditions. (c) 2008 Elsevier Ltd. All rights reserved.