Many measurements of earth-space radio wave depolarization from 10 to 30 GHz have been made in recent years. This review relates the results from these measurements within the framework of theoretical relationships derived from rain and ice depolarization models. The review includes measured statistical relationships between depolarization and rain attenuation and contains cumulative statistics showing the relative frequencies of occurrence of rain and ice depolarization. Depolarization is usually strongest for circular polarizations and for fixed linear polarizations oriented 45° from vertical and horizontal. Depolarization is usually minimized for fixed vertical and horizontal polarizations. For frequencies up to 30 GHz and elevation angles ranging from 10° to 50°, amplitude ratios of ice and rain depolarization are approximately proportional to frequency and to cos2 θ/sin θ, where θ is the path elevation angle.