Patiotemporal Patterns of Rainfall Variability and Their Influence onAgricultural Productivity in Somalia, 1983 to 2023

Abstract

Rainfall variability is a central determinant of agricultural performance in Somalia, where the great majority of cultivated land depends entirely on seasonal precipitation. This study examines the spatiotemporal structure of rainfall across Somalia's eighteen administrative regions between 1983 and 2023 and evaluates its relationship with national crop production. Monthly precipitation totals were derived from the Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) archive and aggregated by season and region, while crop production records were obtained from the Food Security and Nutrition Analysis Unit for Somalia. Regional rainfall totals were compared across the four Somali seasons, and the association between annual rainfall and crop output was tested using Pearson correlation and linear regression. The results show a pronounced north to south precipitation gradient, with southern regions such as Bay and Lower Shabelle receiving more than 490 millimetres annually and northeastern and central regions such as Bari and Mudug receiving less than 350 millimetres. The Gu season contributed between 36.0 and 55.9 percent of annual rainfall across regions, the Deyr season contributed between 17.4 and 44.5 percent, and interannual variability, measured by the coefficient of variation, ranged from 12.3 to 27.5 percent. Annual rainfall was positively and significantly associated with crop production (r = 0.68, p < 0.05), with each additional millimetre of rainfall associated with an estimated increase of 285.7 metric tonnes in national output, although considerable scatter around this relationship indicates that non-climatic factors also shape production outcomes. These findings point to the need for region-specific water management and adaptation strategies rather than a single uniform national policy.