A weather radar's resolution volume is generally determined by beam and pulse widths. Recently, a single-antenna interferometric technique was developed to measure cross-beam and radial wind using angular and range interferometry. Here it is shown that the interferometry technique can refine radar resolution. The technique for resolution refinement is based on the fact that the cross-correlation function of signals from two resolution volumes is contributed only by scatterers in the shared volume. Therefore all the radar measureables derived from cross-correlation estimates have a resolution of the shared volume size rather than a radar resolution volume size. The performance of the technique depends on the shape of beam/range-weighting functions and relative sample error. A sharp change at the edges of the weighting function and low sidelobes are important for resolution refinement using weather radar interferometry.