Daytime visible MODIS imagery have been used to produce climatologies of cloud frequency at moderate resolution (~ 5 km) for the entire earth and at high spatial resolution (~250 m) for most land areas. From these we can describe the seasonal cycle of cloudiness and also the mid-day diurnal tendency of cloudiness (estimated from the cloudiness change between the Terra and Aqua mean cloudiness) at unprecedented spatial resolution. These cloud frequency fields can be used in a wide range of applications, including: 1) as an aid to short-range forecasting of weather, 2) for the validation of mesoscale model-generated cloud fields, 3) the mapping of solar energy potential in complex terrain, and 4) explaining the detailed distribution of individual species or biotic zones. We have used routinely available data and made our products available on web sites for wider access. This talk will describe some of the highlights of these data sets and explain how the work is a consequence of experience gained while one of the authors was a student of Dr. Krishnamurti many years ago.