Polarization is a property of light widely used as a source of additional information in astronomy. The primary source of polarization in the atmosphere is the scattering by gas molecules although meteorological conditions, sky pattern, underlying surface reflectance, etc. may influence the observed sky polarization. In order to explicate polarization measurements correctly, it is important to understand how partially polarized skylight varies. We present results for the daytime sky degree of polarization. Our equipment includes linear polarization filter attached to a photo camera as well as digital polarization camera. We determine the dependence of polarized daylight on the peculiarities of the landscape, altitude of the observer and the season.