Degree of linear polarization maps of W Hya observed with SPHERE-ZIMPOL. The top and bottom rows show the data of W Hya obtained on 2015 July 8 (phase 0.92, Paper I) and on 2016 March 23 (phase 0.54), respectively. The images observed at 645 nm (CntHa, continuum), 656.3 nm (NHa, Hα), 717 nm (TiO717, TiO band), 748 nm (Cnt748, continuum), and 820 nm (Cnt820, continuum) are shown from the left to the right. At each wavelength, the same color scale is used for the 2015 and 2016 data, which makes it easier to recognize that the degree of polarization measured in 2016 is systematically higher than that measured in 2015. North is up, east to the left in all panels.