Some evidence is shown for the hypothesis, that an effective evaporation of absorbed water is important for the durability of organic coatings. By cycling the temperature and measuring electrochemical impedance spectra it turned out that those coatings gave excellent reproducible conditions after each cycle, which also showed superior performance during outdoor weathering. Whereas the measured coating capacity showed the expected dependence from the coating thickness, the coating resistance gave no sign of a correlation with the thickness of corrosion protection barrier coatings. But the Arrhenius-type temperature dependence of the coating resistance gave astonishing results: independent from the chemical nature of the coating material the Arrhenius activation energy correlated with the coating thickness. (C) 2004 Published by Elsevier Ltd.