In this work, we have prepared a series of samples with five representative surface wettabilities: i.e. superhydrophilic, hydrophilic, critical, hydrophobic and superhydrophobic. These samples were in situ observed the freezing process of water droplets on clean and artificially contaminated surfaces to investigate the relationship between surface wettability and ice formation. Ice accretion was also tested by spraying supercooled water to samples at different horizontal inclination angles (HIA). Surface topography was proved to be essential to the icing through heterogeneous nucleation. However, the correlation between surface wettability and ice formation was not observed. Finally, we found that the superhydrophobic surface clearly exhibited reduced ice accumulation in the initial stage of ice formation associated with the lower sliding angle (SA) of water droplets. (C) 2010 Elsevier B.V. All rights reserved.