The Inter-Annual Variability of Rainfall Onset and Its Implication on Crop Planting in Selected East Africa Countries

The inter-annual variability of rainfall onset and crop replanting in East Africa (EA) was assessed using daily estimated data from climate hazard group infrared precipitation (CHIRPS Ver2.0) monthly Sea Surface Temperature (SST) indices [Indian Ocean Dipole (IOD) El-Ni?o Southern Oscillation (ENSO) at NINO3.4 region] the National Center for Environmental Prediction (NCEP) Atmospheric Research (NCAR). covered a period 40 years from1981 to 2020. methods cumulative mean rainfall, percentage date departure (PODD), Mann-Kendall (MK) trend test, student t-test, correlation were applied analysis. results showed that early with dry spell (WDS) consideration frequently occurs Uganda between first second dekads September, while late WDS December over central Northern Kenya as well Northeastern highlands, parts northern coast unimodal regions Tanzania. Rainfall no (WnDS) portrayed an average 10 days before occurrence true WDS, maximum (ODD) above 30 across Rift Valley area highlands high chance minimum ODD is seen entire around Lake Victoria. However, few regions, such Nakuru (Kenya) Gulu Kibale (Uganda), Gitega (Burundi), revealed slight positive linear others negative trend. Significant patterns SST (IOD NINO 3.4) discovered Kenya, areas along Indian (over Tanzania’s Coast). Inter-annual relationship dates IOD (NINO3.4) exhibits coefficient r = 0.23 (r 0.48) 0.44 0.36) Kenya. On other hand, Burundi Tanzania region). A PODD observed, ranging 40% 70% strong observed Tanga Pwani Region These findings will help farmers understand appropriate time planting, socio-economic activities strongly depend on rainfall.