Abstract— Measurements of the albedo of various surfaces in open grounds show significant differences for solar UVB radiation and total solar radiation (0.3–3μm). Above grassland, that albedo for solar UVB radiation is significantly smaller than that for total solar radiation (UVB: 1.3%, total: 20.7%); contrary to that, the albedo for UVB radiation is significantly higher above new dry snow (UVB: 94.4%, total: 87.0%). Consequences resulting therefrom are being quantitatively discussed with respect to the solar radiant exposure of individuals standing outdoors. Keratitis Solaris, for example, hardly occurs in snow-free terrain, even at high solar irradiance in summer; it occurs, however, in snow-covered terrain, in spite of low solar irradiance in winter and spring.