An operational real-time adjusted radar-automatic weather station (AWS) rain rate (RAD-RAR) system, using 10 radars of the Korea Meteorological Administration (KMA), has been developed for the South Korea region. The procedure of the RAD-RAR system consists of four steps for real-time operation: 1) the quality control of volumetric reflectivity for each radar, 2) the computation of the rain-gauge rain rate every 10 min. within each radar, 3) the real-time (updated every 10 min.) rainfall estimation by the Z-R relationship minimizing the difference between the 10-min constant altitude plan position indicator and rain-gauge rain rate based on window probability matching method (WPMM) and by the real-time bias correction of RAD-RAR conducted at 10 min. intervals for each radar by making the bias, and 4) the composition of estimated rainfall data of the 10 radars. It is noted that this RAD-RAR system is available only for summer rainfall cases with the absence of bright band around 1.5 km in height, as the system does not include bright band correction. The performance of RAD-RAR was examined for the 10 heavy rainfall events of 2006, and we obtained results suggesting that the real-time Z-R adjustment of RAD-RAR is better in terms of the agreement with the rain-gauge rain rate than that of the previously fixed Z-R relationship, and the additional bias correction of RAD-RAR yields slightly better results. A square of correlation coefficient R²=0.84 was obtained between the daily accumulated observed and RAD-RAR estimated rainfall.