Although operational weather forecasting centres are increasingly using global coupled atmosphere-ocean-ice models to replace atmosphere-only models for short-term (10-day) weather forecasting, the influence of sea ice on such forecasting has yet to be fully quantified, especially in the Southern Ocean. To address this gap, a polar-specific version of the Weather Research and Forecasting model is implemented within a circumpolar Antarctic domain to investigate the impact of daily updates of sea-ice concentration on short-term weather forecasting. A statistically-significant improvement in near-surface atmospheric temperature and humidity is shown from +48 hours to +192 hours when assimilating daily sea-ice concentration into the model. Improvement in model performance is enhanced from July to September, which is the period of late sea-ice advance. Regionally, model improvement is shown to occur in most sea-ice regions, although the improvement is strongest in the Ross Sea and Weddell Sea sectors. The surface heat balance also shows remarkable improvement in outgoing radiative heat fluxes and both sensible and latent heat fluxes after 48 hours. This research demonstrates the non-negligible effect of including daily updates of sea-ice concentration in numerical weather forecasting and indicates the necessity of implementing a fully coupled atmosphere-ocean-ice model in operational high-latitude southern hemisphere weather forecasting.