This investigation focuses on developing a better understanding of the assorted mechanisms controlling the global
distribution of diurnal rainfall variability. The horizontal distributions of precipitation's diurnal cycle, based on eight
years of TRMM Microwave Imager (TMI) and TRMM Precipitation Radar (PR) measurements involving three TRMM
standard algorithms, are analyzed in detail at various spatiotemporal scales. Results demonstrate the prominence of the
late-evening to early-morning precipitation maxima over oceans and the mid- to late-afternoon maxima over continents,
but also reveal a widespread distribution of secondary maxima occurring over both oceans and continents, maxima
which generally mirror their counterpart regime's behavior. That is, many ocean regions exhibit clear-cut secondary
afternoon precipitation maxima while many continental areas exhibit just as evident secondary morning maxima.
Notably, this investigation represents the first comprehensive study of these secondary maxima and their widespread
nature when analyzed using a global precipitation dataset. The characteristics of the secondary maxima are thoroughly
mapped and described on a global grid. In addition, a Fourier harmonic decomposition scheme is used to examine
detailed amplitude and phase properties of the primary and secondary maxima -- as well as tertiary and quartern modes.
Accordingly, the advantages, ambiguities, and pitfalls resulting from using harmonic analysis are also examined.