No matter where you live, rain seems to fall more often at certain times of day, whether it is seen in the daily afternoon rainstorm or a typical overnight shower. Indeed, statistically, long-term average rainfall tends to cluster at certain times of the 24-hour cycle, but that time frame varies depending on location. A team of scientists led by postdoctoral researcher Takatoshi Sakazaki at UH Mānoa’s International Pacific Research Center (IPRC) has analyzed satellite-based observations and computer model simulations of tropical rainfall variation throughout the day in an effort to determine the root cause of the temporal patterns. Their results, published recently in Geophysical Research Letters, show that daily tropical rainfall distribution is significantly shaped by heating of the upper atmosphere.