This dataset is used in the AMT manuscript titled:"Empirical Model for Backscattering Polarimetric Variables in Rain at W-band: Motivation and Implications"Myagkov et al., 2025. The dataset was collected using a W-band radar in a low-turbulence environment at three different locations. The selection of the spectra was conducted according to Chapters 3.1-3.3 of the AMT manuscript. Data for the three locations (1, 2, and 3; see the publication for details) are saved in the following *.mat files: 'Germany.mat' (47°48’03"N, 11°00’40"E; July 2021 – October 2021; 2,127 spectra) 'China.mat' (31°14’N, 121°28’E; June 2022 – December 2022; 3,407 spectra) 'Italy.mat' (44°40’55"N, 8°37’29"E; May 2023 – May 2024; 9,021 spectra) The files can be opened with matlab (tested with version R2022a). Each file contains the following variables: s.spH and s.spV: Spectra of radar reflectivity for horizontal and vertical channels, respectively [dBZ] s.spR: Real part of covariance spectra [mm^6 m^-3] s.spI: Imaginary part of covariance spectra [mm^6 m^-3] s.nH and s.nV: Spectral noise power in horizontal and vertical channels, respectively [mm^6 m^-3] s.Nyq: Nyquist velocity [m s^-1] s.dR: Range resolution [m] s.spZdr: Spectral differential reflectivity [dB] s.spDelta: Spectral differential phase [°] s.spRhohv: Spectral correlation coefficient s.range: Range [m] v: Doppler velocity [m s^-1], roughly corrected for air motions and adjusted for the elevation angle Radar measurements were performed at an elevation angle of 30°.