The methods used to determine effective cloud fraction (cloud fraction times cloud emissivity at 11--14 μm) and cloud top pressure from analysis of HIRS2/MSU sounding data are described. Identical procedures are used day and night so as to allow for meaningful day-night difference fields. Results are shown for June 1979. The monthly mean effective cloud fraction is 43.4%, resulting from a 45.2% value at 0300 LT and 41.6% at 1500 LT. The retrieved single-day cloud field for June 11 shows good agreement with high spatial resolution visible and infrared imagery. ¿American Geophysical Union 1987