Total water vapour (TWV) measurements are rare in Antarctica, and therefore our knowledge about the spatial and temporal TWV variability is limited. Model simulations can help to close this gap and to understand the driving factors (like storm strength and variability). Measurements are available from radiosounding and can be derived indirectly from ground based GPS observations.The regional climate model HIRHAM4 is used to get a better insight on the Antarctic climate in the last four decades. This model is driven at its boundaries by ERA40 reanalysis data.A comparison of Antarctic TWV between measurements (radiosounding and GPS), reanalysis data (NCEP, ERA40 and ERA Interim) and HIRHAM4 simulations is presented. Additionally the uncertainties in both measurements and simulations are quantified. On the Antarctic Peninsula the correlation between the different data is high. Contrary for continental stations, HIRHAM tends to be too dry. To explain the differences between the different data sets, the synoptic activity and the wind direction is analyzed.