For mapping daily rainfall over East Africa, a method is used which emphasizes distribution rather than rainfall amount. Isohyets are unsuitable for synoptic studies.
Daily rainfall analyses show large-scale systems which develop and persist over periods of days. Changes of type continually take place against background seasonal patterns. Day-to-day evolutions are frequently untypical of seasonal trends. There is little evidence of mobile features. Patterns do not take the form of zonal bands in preference to other shapes.
Statistics describing the scale, structure and persistence of rain areas are given. Regional differences are discussed.