Altitude, brightness, and occurrence rate of polar mesospheric clouds (PMCs) with respect to kinetic temperature, pressure, and water vapor volume mixing ratio (VMR) in the ice formation area are studied. Cloud and atmospheric parameters are measured by the Optical Spectrograph and Infrared Imager System and by the Sounding of the Atmosphere using Broadband Emission Radiometry satellite instruments, correspondingly. The analysis has been done for all northern and southern PMC seasons of 2002–2008 for both zonal averages and nearly simultaneous common volume measurements performed by two instruments. It has been found that PMC peak altitudes correlate well with mesopause altitudes, although the former experience lower seasonal variability. Mesopause temperatures anticorrelate with PMC occurrence rates and, in the Northern Hemisphere, show larger seasonal variability at high latitudes poleward of 75°N compared to 55°N–65°N. OSIRIS PMC brightness correlates with the vertical extent of the frost area and water vapor VMR below PMC (hydration effect) and anticorrelates with the mesopause temperature and water vapor VMR in the frost area (freeze-drying effect).