A “stratospheric fountain”, or area where air enters the stratosphere from the troposphere, is postulated based on an analysis of global 100 mb monthly mean temperatures. The temperature threshold is calculated from the observed global stratospheric water mixing ratio and fulfills the requirement of preserving low stratospheric humidity. The fountain occurs over the western tropical Pacific, northern Australia, Indonesia, and Malaysia in the November–March period and over the Bay of Bengal and India during the Monsoon. It is suggested that the major portion of the stratospheric air supply enters through these areas with most of the exchange occurring in the November–March period. Methods are proposed for substantiating the existence of the stratospheric fountain.