Raw weather radar reflectivities are processed and registered to the ground before radar rainfall measurements are used conjunctively with rain-gauge data to produce areal surface rainfall estimates. However, there are several factors causing errors in the returned power of weather radar signals, as well as other sources of error affecting the accuracy of radar rainfall measurements. In this study, several deterministic corrective techniques are applied to the digital processing stage of raw radar data to consider a number of sources of error, namely non-rainfall echoes, signal attenuation and wind effect. The results indicate that the deterministic techniques are still a necessary step for the ultimate improvement of surface rainfall estimates by the use of weather radar.