Refinements to a prognostic scheme of skin sea surface temperature (SST) are proposed and tested. The refinements consist of two modifications of a Monin-Obukhov similarity function for stable conditions and mixing enhancement by the Langmuir circulation. The modified scheme is tested with the European Centre for Medium-Range Weather Forecasts model. The modified scheme shows better agreement of the diurnal SST amplitude with estimates from satellite observations. The scheme is also validated with moored buoy observations of the Arabian Sea Mixed Layer Dynamics Experiment. The off-line model with the modified scheme reproduces the observed diurnal SST variability well. Additionally, it is found that the parameterization of the effect of the Langmuir circulation enhances ocean mixing and reduces the diurnal variability of SST under wavy conditions.