A study of the vertically integrated fields of water vapor and its transport on a planetary scale derived from aerological data taken during the IGY (International Geophysical Year) is presented. The focus is upon the seasonal variability in these fields, with maps of the total zonal and the total meridional flux of water vapor given for each of two semester seasons. The analyses are discussed in the light of various climatological and hydrological considerations. Results from the analysis of our aerological data are used to study the balance of water on zonal and planetary scales, and comparisons are made with evidence provided from climatological sources. The aerological approach to the study of the hydrological cycle is seen to be a valuable one.