The influence of oceanic and atmospheric drivers on Djibouti’s rainfall variability

Rainfall variability presents a major challenge for climate-sensitive sectors in arid and semi-arid regions such as Djibouti, where livelihoods depend heavily on rain-fed systems. This study investigates the seasonal and interannual variability of rainfall and temperature in Djibouti during 1981–2024, focusing on spatial patterns and their relationships with large-scale ocean-atmosphere drivers. Results confirm a bimodal rainfall regime with primary peaks during July-September (JAS) and secondary peaks during March-May (MAM), associated with the seasonal migration of the Intertropical Convergence Zone. The principal rainy season (JAS) contributes approximately 45.8% of the annual rainfall, especially across the western highlands, and in some locations extends into November, increasing its contribution to more than 60% of the annual total. In contrast, coastal and eastern regions tend to experience more irregular and discontinuous rainfall patterns. Rotated Empirical Orthogonal Function analysis identifies distinct spatial modes of rainfall variability, with western Djibouti dominating variability during JAS, reflecting strong monsoonal influence. The October-November (ON) season displays greater spatial fragmentation, especially along coastal zones, while December-February rainfall shows comparatively higher spatial coherence linked to synoptic-scale systems and regional convergence zones. Temperature extremes are most pronounced during the boreal summer, particularly in lowland areas. Correlation analysis reveals strong associations between seasonal rainfall variability and sea surface temperature anomalies in the western Indian Ocean, Red Sea, and Gulf of Aden. Large-scale climate modes especially the Indian Ocean Dipole and El Niño-Southern Oscillation, exert a significant influence on rainfall seasonality. Positive IOD phases are linked with enhanced ON rainfall through increased moisture transport, whereas La Niña conditions tend to strengthen JAS precipitation by promoting circulation patterns that favor moisture convergence over the region. By identifying the dominant seasonal large-scale and regional drivers of Djibouti’s rainfall and their spatial modes of influence, this study advances the current understanding of the country’s climate dynamics and highlights key ocean-atmosphere signals that can be monitored to enhance seasonal rainfall predictability. These insights provide a stronger scientific basis for improving seasonal forecasting, early warning systems, and climate-resilient planning in Djibouti and the broader Horn of Africa.