Abstract The Weather Surveillance Radar–1988 Dopplers (WSR‐88Ds) are an operational network of S‐band, dual‐polarization radars in the United States. Currently, replacement options are being considered for the next generation of weather radars. One option is dual‐polarization phased array radar (PAR), which employs electronic beam steering to provide faster volumetric updates. The Advanced Technology Demonstrator (ATD) is a research PAR that is being used to evaluate the feasibility of PAR technology. Presumably, the improved temporal resolution of the PARs will lead to more accurate radar‐based quantitative precipitation estimation (QPE). However, PARs require more complex calibration, especially for dual‐polarization observations. To test this hypothesis, the ATD and KOUN are used. From radar data over rain gauge locations, rainfall accumulations are calculated and compared to rain gauge observations. We show that, overall, PAR‐based QPE can perform 16.1% better than current WSR‐88Ds, in part due to the <60‐s low‐level sampling rate of the ATD.