This paper assesses the use of wet/dry cyclic laboratory corrosion tests that can provide information on the protective capacity of weathering steels in short times. Two steels were considered, a weathering steel ASTM A 242 Type 1 and a plain carbon steel (as reference), that were exposed in the atmosphere of Madrid (3 years) and in the following laboratory wet/dry cyclic tests: Cebelcor (10(-4) M Na2SO4) (945 h), Kesternich (0.2 L SO2) (2160 h) and Prohesion (2160 h). Characterisation of rust layers was done by XRD, FTIR, SEM, SKP and EIS. Wet/dry cyclic tests make it possible to shorten the testing time to assess in laboratory the protective capacity of rusts formed on weathering steels in the atmosphere. Some analogies between experimentation in the field and in the laboratory have been established. (C) 2013 Elsevier B.V. All rights reserved.